Question

In 25 days the earth pick up 6×10to the power 8 pounds of dust from the atmosphere how much dust will it pick up in 15 days

Answer 1

In 25 days the earth picks up= 6×10^8pounds
In 1 day the will pick up =6×10^8/25
In 15 days the earth will pick up=
6×10×10×10×10×10×10×10×10×15/25
36×10^7 or 3.6×10^8 (ans)

Answer 2

$\bold{3.6 \times 10^{8}}$ dust would be picked up in 15 days.

Solution:  

Dust picked up by Earth in 25 days = $6 \times 10^{8}$  pounds

In order to find picked up by the earth in 25 days, the value should be divided by 25.

Dust taken by Earth in 25 day = $\frac{6 \times 10^{8}}{25}$

Dust taken by Earth in 15 days = $\frac{15 \times 6 \times 10^{8}}{25}$  

                                           $=\left(\frac{90}{25}\right) \times 10^{8}$

By division of 90 by 25 we get 3.6,

Dust picked up by Earth in 15 days = $\bold{3.6 \times 10^{8}}$ pounds.