3 math problems 10

1 Let A transport x per hour, then B per hour, according to the title, 16 * x + 262 = 16 * x = ?Do the math yourself.

2. Set the total number of people x

x*60%-5=x*7/20+16

x=?3 Set the interest rate to x

4000+4000*x+(4000+4000*x)*x=

1: Let the work efficiency of A be x tons of days, then B is tons of days.

16x+262=

x=802: There are x people in all grades.

x=2203: Set the annual interest rate to x

4000(1+x)(1+x)=x=

Question 1: 1920

Question 2: Solution: Let the total number of people be x.

x-(7/20x+16)=

x=220 Question 3:

Solution: Set the annual interest rate to x

4000(1+x)(1+x)=

x = approximately equal to).

Question 1: Let the work efficiency of A be x tons of days, then B is tons of days, and the total amount of work on this day is yy-x*16 24=262

Solution: x=1920

Question 2: If the total number of people is x, the number of boys is y, and the number of girls is z, then:

60%x-5=z

7/20x+16=y

z+y=x solution: x=220

Question 3: Set the annual interest rate as x,4000+4000x+(4000+4000x)x=

That is, 4000(1+x)(1+x)=

Solution: x=

1.From the logarithmic arithmetic rule:

f(a)=lg(1-a)-lg(1+a)

f(-a)=lg(1+a)-lg(1-a)=-f(a)=-b2.Let x=y=0 get:

f(0)=2f(0)

So f(0)=0

Let y=-x get:

f(0)=f(x)+f(-x)

So f(-x) = -f(x).

So f(x) is an odd function.

Because f(x) is an odd function.

So f(-2)=-f(2)=-1

1. Solution: Let the radius be r decimeters, then.

2r + r =

Solution: r =

i.e. the radius is decimeter.

ps: See clearly whether the unit is centimeters or decimeters, calculated, the circumference of the semicircle is actually half of the whole circle plus the diameter.

2. Solution: From the meaning of the title, the three sides of the right triangle are: 6cm, 8cm, and 10cm.

Let the height on the hypotenuse of the right triangle be h, then.

1 2 x 5 x h = 1 2 x 3 x 4 solution: h=

ps: The circumference of the triangle can be known conditionally is 24 cm, and the length of the three sides can be known from the length ratio of 3 12, 4 12, 5 12 respectively, then the side length can be obtained. Then the area is equal, and the slope height is calculated by using the area formula.

3. Solution: If the two kinds of fruit sugars are A, B and the unit price of A is X yuan, then the unit price of B is 2X yuan.

Because the weight ratio of A to B is 2:1

Therefore, in 300 kg of fruit candy, A has 200 kg, B has 100 kg, and the unit price of 300 kg of fruit sugar is 12 yuan, 200x + 100 x 2x = 12

Solution: x= i.e. 2x=

Therefore, it turns out that the unit price of these two kinds of fruit candy is yuan and yuan respectively.

1.A semicircle has a circumference of centimeters, what is its radius in decimeters?

r=r=r=2.With 24 cm of iron wire to form a right triangle, the length ratio of the three sides of this triangle is 3:4:5, what is the height of the hypotenuse of this right triangle in centimeters?

Suppose one is x, then the three sides are 3x, 4x, and 5x respectively, so 3x+4x+5x=24

12x=24

x=2 then the three sides are 6, 8, and 10 respectively

With the equal area method: the product of the right-angled side = the hypotenuse height on the hypotenuse 6 8 = 10 the height of the hypotenuse.

The height of the hypotenuse = 3The unit price ratio of the two fruit candies is 1:2, the weight ratio is 2:1, and now the two fruit candies are mixed together with a total weight of 300 kilograms, and the unit price is 12 yuan, so what is the unit price of the original two kinds of fruit candies?

Solution: Let the unit price of the first fruit candy be x weight is 2y, then the second is 2x weight is y2y + y = 300

y=100x×2y+2x×y）÷300=12

4x×100=3600

x=9, so the original unit price of these two kinds of fruit candy is 9 yuan and 18 yuan respectively.

1.Its radius is: decimeters.

Solution: centimeter = decimeter.

The radius is equal to half of the diameter, so divide by 2=

2.The height on the hypotenuse is 10 cm.

Solution: Because the hypotenuse of the triangle is the longest, the ratio of the hypotenuse is 5, so: 24 times 5/12

3.It turns out that the unit price of these two kinds of fruit candy is 4 yuan and 8 yuan respectively: 12 times 1/3 = 4

12 times 2/3 = 8

1.2r+ r= r=2cm=decimeter.

x=2 then the three sides of the triangle are 6 8 10, so the height on the hypotenuse is 6*8 10=

3.Let the unit price of the first fruit be x and the weight be y, and the unit price of the second fruit be 2x and the weight be 1 2y

y+1 2y=300 x+2x=12 gives x=4 y=200

Therefore, the unit price of the first fruit is 4 yuan and the weight is 200 kilograms.

The unit price of the second fruit is 8 yuan and the weight is 100 kg.