1.The distance between a and b is 420km, one is asphalt road and the other is dirt road. Eight hours later, the car drove from a to b. It is known that its speed is 60 kilometers per hour on the asphalt road and 40 kilometers per hour on the dirt road. How many kilometers is the dirt road?

Solution: If the dirt road is x kilometers long and the asphalt road is 420-X kilometers long.

X÷40+(420-X)÷60=8

X÷40+(420-X)=8×60

X= 120

When the squadron went camping for the first time, the cook asked how many people there were. The squadron leader replied: One person has a rice bowl, two people have vegetable bowls, three people have soup bowls, and you have 55 bowls here. How many people do you count?

There are x people

X+ 1/2X+ 1/3X=55

6/ 1 1X=55

X=30

In the division formula, the sum of dividend, divisor, quotient and remainder is 127. Suppose the quotient is 3 and the remainder is 2, what is the divisor?

Solution: Let the divisor be x, then the dividend is 3x+2.

X+3X+2+3+2= 127

4X+7-7= 127-7

4X= 120

X=30

4. There are 22 participants from two schools, A and B. The number of participants in A school is one fifth less than that in B school. How many participants are there from schools A and B?

Let a school be X and B school be 22-X.

(22-X)- 1/5X= 1

0.8X=23

X=28.75

Harry Potter took part in the math contest, and he got 68 points. The standard of grading is: 20 points for each pair and 6 points for each mistake. It is known that he did twice as many right questions as wrong questions, and he did all the questions. How many questions are there in this test paper?

Solution: Suppose Harry Potter answered the 2X question correctly and the X question incorrectly.

20×2X-6X=68

40X-6X=68

34X=68

X=2

Correct answer: 2×2=4 questions.

* * * Yes: 4+2=6 questions.

6. A team of young pioneers crossed the river by boat. If each ship takes 15 people, there are still 9 people left. If each ship takes 65,438+08 people, there are only 65,438+0 people left. How many ships are there?

Suppose: there are x ships.

Let the number of ships be x, then

( 15X+9)÷ 18 = X- 1

15X+9= 18X- 18

3X=27

X=9

7. There are two piles of sand on the construction site. The first pile is 85 tons more than the second pile. After using 30 tons of sand for each pile, the first pile is twice as much as the second pile. How many tons are there in two piles of sand?

Solution: Let the second pile be X, then the first pile is x+85.

2×(X-30)=X+85-30

2X-60=X+55

X= 1 15

1 15+85=200 tons