Su Jiaoban fifth volume mathematics supplementary exercise answer 70 pages 3~4 questions.

You should have learned to solve equations, remember I learned to solve equations in the fourth grade.

1. solution: let x pages be one centimeter thick.

2.4x=256

X = 2.4 in x=256 (integer cannot be divisible)

3.6x = 2.4×3.6 inches 256.

3.6x=384

A: There are about 384 pages.

2. Solution: Suppose the advertising fee is X yuan per second.

30x×(2*7)=357000

420x=357000

x=357000÷420

x=850

A: Pay the advertising fee by the second, 850 yuan.

3. Solution: Let a * * * earn back X yuan.

1.5×20- 17.2=x

30- 17.2=x

x= 12.8

A: A * * * can earn back 12.8 yuan.

I wish you progress in your studies.