Elementary School Equation One, thank you!! A primary school math Olympiad problem to find equations

Solution: Set the time to x hours.

70x+20x=270

90x=270

x=3A: It takes 3 hours for a car and a bicycle to meet.

The travel time is x hours.

70x+20x=270

x=3 A: The car and bicycle meet after 3 hours.

Solve the encounter over x hours 70x+20x=270

90x=270

x = 3 for 3 hours.

Solution: Let the car and bicycle meet after x hours.

70x+20x=270

90x=270

x=3 A: The car and bicycle meet after 3 hours.

Set a travel time of x hours.

1.If the two cars travel relative to each other, then 70x+20x=270 x=3 hours Solution: 270 (70+20)=3 (hours).

2.If two cars are driving in the same direction, then 20x+270=70xx=hours.

Set a travel time of x hours.

If you are facing (reverse) driving, then 70x+20x=270 gives x=3 hours.

If the car is chasing (in the same direction), then 20x+270=70x, the solution is x=hours.

Set up to meet after x hours. then 70x+20x=270 x=3

X that bloomed last year, 2x+55 that didn't bloom, a total of 3x+55 x+100 that bloomed this year, 2x-45 that didn't bloom, which is exactly 4 times that of the arrowhead that bloomed and didn't bloom, that is, x+100=4 (2x-45).

Solution x=40

So a total of 3x+55=175 trees.

Suppose the x trees that bloomed last year are.

Those that did not bloom last year (2x+55), those that bloomed this year (x+100), and those that did not bloom this year (x+100) 4, x+2x+55=5 4 (x+100), x=40, for a total of 175

Let the non-flowering be x and the flowering being y

Then we can get the system of equations 2y+55=x

4x-y=500

x=135 y=40

x+y=175

Assuming that the number of arrowheads that bloomed last year is x, there are.

The number of arrows that did not bloom last year was (2x+55), the number of arrows that bloomed this year was (x+100), and the number of arrows that did not bloom this year was (x+100) 4, because the total number of arrows was certain, so x+2x+55=5 4 (x+100), the solution was x=40, and the total number was 175

Let the ages of the two brothers be x and y, and the age of the brothers after three years is 26 years old, that is, (x+3)+(y+3)=26, (brother is x, brother is y) simplified, x+y=20;

The ratio of the younger brother's age this year to the age difference between the two brothers is exactly 2:1, that is, y (x-y)=2 1, simplified, x=;

Substituting x+y=20, we get: y=20 , x=12;

Three years later, the elder brother is 15 years old (12+3) and the younger brother is 11 years old (8+3).

Let's say: The younger brother's age this year is x years old, according to the title: x=2 (elder brother - x), and the elder brother's age today is 3 2.

3/2x+3)+(x+3)=26

5/2x=20

x = 8 years old. My brother is 8 3 2 = 12 years old.

Three years later, the younger brother is 8 + 3 = 11 years old, and the older brother is 12 + 3 = 15 years old.

The younger brother is x this year, that (younger brother + 3 + older brother + 3) = 26 The elder brother's age is 20-xx: 20-x-x = 2:1

x=8, the younger brother's current age is 8, and each is 12

3 years later younger brother 11, each 15

Subtract a from both sides

700000=49a+35

700000=7x7a+5x7

Divide by 7,100,000 on both sides = 7a + 5

Subtract 599995 = 7a from both sides

Divide by 714285=a on both sides

Transposition a = 14285

Solution: If there are 3x pages of read at the beginning, then there are 5x pages of unread content.

3x+33）：（5x-33）=4:3

3x+33）×3=（5x-33）×4

9x+99=20x-132

20x-9x=99+132

11x=231

x = 21 The book has 21 3 + 21 5 = 168 pages.

Let football ** be x yuan, then the ** of basketball is 2x-30 yuan, and the equation 5x+5x(2x-30)=870 can be obtained from the meaning of the question to get x=68, so football ** is 68 yuan, and basketball ** is 106 yuan ps: x is multiplied.

Let football x yuan, basketball 2x-30, then 5x+(2x-30)5=8705x+10x-150=870, 15x=970, x=64, then basketball = 2x-30=98 (yuan).

then basketball 98 yuan. Football 64 yuan.

Solve a soccer ball for x-yuan basketball 68 2 30

5x+10x-150＝870 ＝156-30

5x+10x ＝870+150 ＝126

5x+10x＝1020

15x＝1020

x＝1020÷15

x＝68

Snake soccer is x-yuan, basketball is 2x-30

then 5x+(2x-30)*5=870

15x-150=870

x=68, then basketball = 2x-30=2*68-30=106 yuan, so football is 68 yuan, basketball is 106 yuan.

Let's assume that soccer ** is x, then basketball is 2x 30, and the equation is.

5（2x－30）＋5x＝870

If you solve the equation x 68, then the basketball is 106 yuan.

Let the football be each x yuan, then 5 * (3 x + 30) = 870 from the title, and x=48 can be obtained, so the football is 48 yuan each, and the basketball is 126 yuan each.

Let the ** of football be x, then the ** of basketball is 2x-30

The equation is: 5 (2x-30)+5x=870

Solve the equation to get: x=68

A basketball and a soccer ball total: 870 * 5 = 174 yuan.

A soccer ball: (174 + 30) * 3 = 68 (yuan).

A basketball: 68 + 30 = 98 yuan.

One basket + one foot = 174 yuan (2 feet - 30) + feet = 174

Foot = 68 baskets = 106

A said to B, "When I was your age, you were exactly three years old. B said to A, "When I grow to your present age, you will be fifteen years old." "How old are A and B this year?

A said to B, "When I was your age, you were exactly three years old. It can be understood that A's age is shortened by a period of time; B said to A:

When I get to your age, you'll be 15. "It can be understood that A's age has increased by a period of time; In this way, there are three time periods, the reduced part, the present part itself, and the increased part, and the difference between these three parts is the difference between 15 years old and 3 years old. So the solution is as follows:

B: 3+4=7

A: 7+4=11

A: A and B are 11 and 7 years old respectively this year.

A is 11 years old and B is 7 years old.

Set A to be x years old and B y years old.

x-y=y-3

x-y=15-x

Solution x=11y=7

15-3) 3=4 (years).

B age 3 + 4 = 7 (years).

A age 7 + 4 = 11 (years).

Draw a comparison of the pictures, and draw three pictures are the age chart of A and B when A is 15, the age chart of A and B now, and the age chart of A and B when B is 2 years old; Comparison shows that (15-3) is 3 times the difference between A and B, and the difference between A and B is 4 years old, and it is easy to get that A is now 11 and B is 7 years old.