Grade 3 Math Application Problems, Urgent !!!

Mom ate 2 pieces, Dad and Mom ate the same amount, so Dad also ate 2 pieces, Xiaoqiang ate 3 8 of watermelon, Dad ate 2 8=1 4 of watermelon, Dad ate 2 8=1 4 of watermelon, and the three of them ate a total of 7 8 of watermelon

Xiaoqiang: 3 divided by 8 equals 3/8

Mom and Dad each eat: 2 divided by 8 equals 1/4

3/8 + 1/4 + 1/4 = 7/8

Dad ate two pieces, Mom ate 2 8 = 1 4 of watermelon, Dad did the same, Xiaoqiang ate 3 8, a total of (2 + 2 + 3) 8 = 7 8, three grams of oil.

Dad: 2 8=1 4 Mom: 2 8=1 4 Xiaoqiang: 3 8

Ate a total of: 2 8 + 2 8 + 3 8 = 7 8

Mom, Dad: 2 pieces each (that is, Dad and Mom eat 1 4 each) Xiaoqiang 3 pieces (that is, eat 3 8).

The three of them ate a total of watermelon: 1 4 + 1 4 + 3 8 = 7 8

Mom: 2 8 = 1 4

Xiaoqiang: 3 8 = 3 8

Daddy = Mommy: 2 8 = 1 4

Total: (Mom*2+Xiaoqiang) 8=7 8

Dad: 2 divided by 8 = two eighths = a quarter.

Mom's and Dad's are the same.

Xiaoqiang: 3 divided by 8 = three-eighths.

In total: (2+2+3) divided by 8 = seven-eighths.

Dad also ate two pieces, 2 8 = 1 4

Mom ate two pieces, 2 8 = 1 4

Xiaoqiang ate three pieces, 3 8

The three of them ate a total of 2 + 2 + 3 = 7, that is, 7 8

Mom is a quarter, Xiaoqiang is three-eighth, and Dad is a quarter A total of seven-eighths.

Dad: 2 8 Mom 2 8 Xiaoqiang 3 8 A total of 3+3+2 8=8 8

Daddy: 2 8=1 4;

Mom: 2 8 = 1 4

Xiaoqiang: 3 8 = 3 8

Three: (2+2+3) 8=7 8;

l Teacher age - student age = student age Pai Qing - 3, teacher age - student age = 39 - teacher age.

It can also be read as: Teacher's age = twice the student's age - 3, and student's age = twice the teacher's age - 39.

So: teacher age + student age = 39 + 3 = 42;

3 (Teacher age - Student age) = 39 - 3 = 36, i.e. Teacher age - Student age = 12.

So the teacher's age is (42 + 12) 2 = 27;Student age is: (42 - 12) 2 = 15.

on 2013-02-18

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In another 2 years, grandpa will be 5 times older than Xiaohong.

Two years later, because two years later, grandpa will be 75 years old and Xiaohong will be 15 years old. 75÷15=5

I don't understand the class and continue to ask, satisfied.

After 2, Xiaohong is 15 years old, grandpa is 75 years old, and grandpa is just 5 times older than Xiaohong.

When Xiaohong is in his teens, multiplied by five equals his grandfather's seventy or eighty.

Obviously when the number is 3,4 is not right, 15x5=75 holds, so it is two years later.

Grandpa is 4 times bigger than Xiaohong. i.e. (73-5*13) 4=Answer.

What is the speed and length of a train that takes 80 seconds to cross a 456-meter-long bridge and 77 seconds to pass through a 399-meter-long tunnel at the same speed?

Analysis: The 80-second journey of this train is "456 bridge length plus car length", and the 77-second distance is also "car length plus tunnel length 399 meters". The distance difference between the two times is 456 399 = 57 (meters), because the bridge and the tunnel can be regarded as a "slow train" with no speed but length when calculating, so the 57 meters are completely completed by the "express" train in 80 77 = 3 (seconds) minutes, so the speed can be found, and then the length of the car can be found.

Solution: The train speed is.

19 (m) train length is.

19 80 456 = 1064 (m).

or 19 77 399=1064 (m).

A: The train speed is 19 meters per second and the train length is 1064 meters.

Let the speed of the train be v meters per second and the length be x meters.

80v=456+x

77v=399+x

v=19x=1064

This train has a speed of 19 meters per second and a length of 1064 meters.

Let the speed and length of the train be x, y, respectively.

80x=456+y

77x=399+y

x=19, y=1064

So the speed of this train is 19 meters per second and the length is 1064 meters.

Solution: Let the speed of the train be v and the length of the train be x, then:

80v=456+x (1）

77v=399+x （2）

Equations (1) and (2) can be solved to v=19 x=1064

112 people. Let there be a person in each row, then a a+12+9=(a+1)(a+1) is solved to a=10

10 10 + 12 = 112 people.

Let there be a person in each row, then a a+12+9=(a+1)(a+1) is solved to a=10

10 10 + 12 = 112 people.

A: 112 people.

1 solution: 3 bottles of drinks are 6 yuan, and the price of each bottle is 2 yuan.

Buy 5 bottles and get 1 bottle free, each bottle is actual ** (5 2) (5 + 1) = 5 3 yuan 36 5 3 = 60 yuan.

2 Solution: If it is all tricycles, there are 60 wheels.

Now there are 78 wheels, and 78-60 = 18 wheels more.

Cars have 4-3=1 more wheels per car than tricycles.

So there are cars 18 1 = 18 cars.

Tricycle 20-18 = 2 units.

3 Solution: small bread per person ** = 100 12 = 25 3 large bread per person ** = 120 16 = 15 2

Because 25 3> 15 2

So try to ride as many loaves as possible.

56 16 = 2 cars and 24 people.

24 people in 2 vans.

So the total amount = 2 120 + 2 100 = 440 yuan.

Question 1: It will cost at least 78 yuan.

1.If you buy 40 bottles, you will get 8 bottles, which is enough for one bottle per person, and the 8 bottles will give away another bottle, and the one bottle sent and the remaining three bottles will be borrowed for a total of five bottles, and you can give another bottle away, and you can return the one bottle you sent, so that it is more than one bottle per person.

2.Buy 39 bottles, use 35 of them to get 7 bottles, and the remaining 4 bottles and 7 bottles to get a total of 11 bottles can get 2 more bottles, so that's a total of that.

39 + 7 + 2 = 48, which is exactly one bottle per person.

3.If you buy 38 bottles, it is 38 + 7 + 2 = 47, which is not enough for one bottle per person.

Question 2: This question is the problem of chickens and rabbits in the same cage.

When the problem of "chickens and rabbits in the same cage" is solved:

Suppose 20 are all tricycles, there should be wheels: 3 * 20 60, 78 60 18 less than the actual one, this is because the 4-wheeled car is counted as a three-wheeled vehicle, each one is less than 4 3 1, so there are 18 1 18 cars, and 20 18 2 tricycles.

It can also be assumed that 20 cars are all cars, and there should be wheels: 4 * 20 80, which is 80 78 2 more than the actual one, this is because the tricycle is counted as a car, and each car is 4 3 1 more, so there are 2 1 2 tricycles, and 20 2 18 cars.

It can also be solved using equations:

There are x tricycles and 20 x cars.

3x＋4*（20－x）＝78 x＝2 20－x＝20－2＝18

Question 3: Plan 1: Rent 3 buses and rent 300 yuan;

Plan 2: Rent 2 buses and 4 vans, the rent is 440 yuan;

Plan 3: Rent 1 bus, 7 vans, rent 520 yuan;

Option 1 is more cost-effective.

It's hard to type, so remember to adopt it.

5=30 yuan 3 5+3=18 bottles 36 18=2 30 2=60 yuan.

2. There are x tricycles. 3x+4(20-x)=78 3x+80-4x=78 x=2 There are 2 tricycles and 18 cars.

100 = 16 120 = 2 15 yuan <2 15 Set up x minivans and y vans for rent. 12x+16y=56 3x+4y=14 (x=2 y=2 2 cars for each of the two types of cars.

Please adopt, dear.

1. 36 (5+1)=6

6*5=30 bottles.

30 3 * 6 = 60 yuan.

2. Set the tricycle to have x amount, and the car to have (20-x) amount 3x+4*(20-x)=78

x=2 cars have 20-2=18 volumes.

3. Rent two small cars and one large car.

1.If you buy x 5 bottles and reach 36, then you can list the equation 5x+x=36, and solve x=6, that is, you need to buy 5*6=30 (bottles), 30 3*6=60 (yuan).

2.The tricycle has 3 wheels, the sedan has 4 wheels, there are x tricycles, the sedan is (20-x), the equation is 3x+4*(20-x)=78, and the solution is x=2, (20-x)=18, so there are 2 tricycles and 18 cars.

The third question is waiting for you.

1. Solution: When the speed of Tiantian is x kilometers, then when the speed of Beibei is (x-5) kilometers, it can be obtained:

10(x-5)=(10-4)x

10x-50=6x

10x-6x=50

4x=50x=The distance between the two places is: 10x (km).

2. Solution: After X years, grandpa is 5 times that of Xiao Ming, and you can get:

71+x=5(11+x)

71+x=55+5x

5x-x=71-55

4x=16x=4, at that time, the grandfather's age was: 71 + 4 = 75 (years old) and Xiao Ming's age was: 11 + 4 = 15 (years old).

1. If the velocity of the solution is x kilometers per hour, then the speed of Tian Tian is x + 5 kilometers per hour, according to the equation of the problem: 10x=(10-4)*(x+5)10x=6*(x+5).

10x=6x+30

4x=30x=km).

Then the distance between A and B is 10*km.

May you learn and progress.

1, with the learned full length as a unit 1, the speed of the bebe is (the full length) 1 10, the speed of sweet is 1 6, the speed difference is 1 6-1 10 = 1 15 The difference in the total length is 1 15, the difference is 5km, and the total length can be calculated: 5 1:15=75km

2. A few years later, grandpa is just 5 times older than Xiao Ming, so draw a line diagram at this time:

Xiao Ming 1 paragraph. Grandpa 5 paragraphs, the difference is 4 stages, and the difference of 60 years (71-11) is 15 years old: 15 * 1 15 * 4.

Seeing that everyone's equations are good, I can't help but write them.

1, Bei Bei and Tian Tian went from A to B at the same time, Bei Bei took 10 hours, 4 hours more than Tian Tian, it is known that the speed difference between the two is 5 kilometers, how many kilometers is the distance between A and B? (Answer with equations).

Solution: When Tiantian's velocity is x kilometers, then when Beibei's velocity is (x-5) kilometers, we can get:

10(x-5)=(10-4)x

10x-50=6x

10x-6x=50

4x=50x=The distance between the two places is: 10x (km).

Xiao Ming is 11 years old this year, and his grandfather is 71 years old this year. A few years later, grandpa is 5 times older than Xiao Ming? How old was Grandpa then? How old is Xiao Ming?

2. Solution: After X years, grandpa is 5 times that of Xiao Ming, and you can get:

71+x=5(11+x)

71+x=55+5x

5x-x=71-55

4x=16x=4, at that time, the grandfather's age was: 71 + 4 = 75 (years old) and Xiao Ming's age was: 11 + 4 = 15 (years old).

1.Let Sweet be x kilometers per hour.

Distance = Sweet Time x Speed = Bebe's Time x Velocity.

10-4)x=10x(x-5)

x = ab distance.

2.Set x years later.

11+x）x 5=71 + x

x =4

Question 1 It is easy to know that the speed of the bebe is slower, so let the velocity of the bebe be x, so the speed of the sweet is x+5, so there is an equation of 10x=(x+5)*6, and the solution is x=, so the distance =

The second question will be set after x years, and the question setting conditions will be met.

Then 71+x=5(11+x) gives x=4

So Grandpa was 75 at that time, and Xiao Ming was 15 at that time

Solution: Set Tiantian to use x hours, Beibei to use x + 5 hours.

Tian Tian used 10-4 = 6 hours.

6x=10（x+5）

6x=10x+50

4x=50x=set x years later.

5（11+x）=71+x

55+5x=71+x

4x=16x=4