It takes x hours to complete the journey, and speed times time equals distance.

45t=90/( 1/2- 1/5)

45t=90*( 10/3)=300

t=20/3

2.

Warehouse A transported X tons of grain to warehouse B..

62+x=( 100-x)*(4/5)

5(62+x)=4( 100-x)

3 10+5x=400-4x

9x=90

x= 10

3.

Suppose there are x people in class one, then there are 90-x people in class two.

75%x+5/6 (90-x)=7 1

3/4x+75-5/6x=7 1

- 1/ 12x=-4

x=48

4.

This section of road is x meters long.

x/6=20%x/2+ 12

x/6-x/ 10= 12

x/ 15= 12

x= 180

5.

The length of this garden is x meters.

2(x+80%x)= 108

2* 1.8x= 108

x=30

30m long and 80% wide * 30 = 24.

The area of this garden is 30*24=720 (square meters).

6.

Suppose A produces X parts, of which B is (1/2)x/60% and C is (1/2)x/75%.

( 1/2)x/60% =( 1/2)x/75%+50

x=300

B is 250 and C is 200.

This batch of parts is 300+250+200=750.

7.

* * * Collect x kilograms of tomatoes.

(62.5%x/6)*3+24=37.5%x

x=384

8.

There are x people in this clothing factory.

25% x( 1- 1/5)( 1+3/ 10)= 156

x=600

9.

Set a bag of rice with x, and set b with x+ 18.

x-6=(x+ 18+6)*62.5%

x=56

10.

The total length of this highway is x kilometers.

x/2-(x/4+x/5)=6

x= 120

1 1.

Let this book have x pages.

[(2/ 15 x)+(2/ 15 x+6)]:x = 3:(3+7)

x= 180

Reread X-[(2/15x)+(2/15x+6)] =126.

12.

Pears have X.

[2 10+ 1/5(x-80)]:(x-80)= 5:4

4 *[2 10+ 1/5(x-80)]= 5 *(x-80)

840+0.8x-320=5x-400