Chen Xiao climbed a mountain from A to B, with a journey of 30.5 kilometers, which took 7 hours. He went up the mountain at a speed of 4 kilometers per hour and down the mountain at a speed of 10 kilo

Chen Xiao climbed a mountain from A to B, with a journey of 30.5 kilometers, which took 7 hours. He went up the mountain at a speed of 4 kilometers per hour and down the mountain at a speed of 10 kilometers per hour. 1, solution: suppose * * * destroys x water bottles.

6x 500 x(5.5/ 10)-( 1 1.5+5.5/ 10)x = 1553.6

3000 x 0.55-( 1 1.5+0.55)x = 1553.6

1650- 12.05 x = 1553.6

12.05x=96.4

x=8

A: * * * destroyed eight water bottles.

2. Solution: Suppose there are X sunny days and (6-x) rainy days in these 6 days.

100x+60x(6-x)=520

100x+360-60x=520

40x= 160

x=4

A: Four of these six days are sunny and two are rainy.

3. Solution: Let A hit X and B hit Y. ..

20x- 12x( 10-x)+20y- 12( 10-y)= 208 x+y = 14

20x- 12x( 10-x)-[20y- 12( 10-y)]= 64x-y = 2

x=8 y=6

A: A hit 8 rounds and B hit 6 rounds.

4. Solution: Let the distance from A to B be X kilometers.

(x/4)+(30.5-x)/5=7

x/20=0.9

x= 18

From B to A, uphill (30.5- 18)/4=3. 125.

Downhill 18/5=3.6

3. 125+3.6=6.725

A: If the speed of going up and down the mountain remains the same, it will take 6725 hours to return from B to A. ..