How to write 13, 14, 15 in the math book exercise 17?

The answer to the question 17 1 1

Solution: Suppose two cars meet in X hours.

( 1 10+80)x=570 x=3

12 exercise 17 answer to question 12

Solution: Let car B drive at the speed of X kilometers per hour.

(68+x)×3.5=455 x=62

13 exercise 17 answer to question 13

Solution: Set up team B to dig X meters every day.

( 12.6+x)×25 = 675 x = 14.4

14 exercise 17 answer to question 14

Solution: Let Ship B travel at the speed of X kilometers per hour.

(x-32.5)× 18=57.6 x=35.7

15 exercise 17 answer to question 15

3x=x+ 100 x=50

16 practice the answers to seventeen thinking questions

Solution: Let a * * * take x times.

5x=3x+6 x=3

The original table tennis is: 5×3= 15 (pieces)

The original badminton is 3×3+6= 15 (pieces).