Question

In 30 days the earth picks up 7.8×10^8 kg dust from the sky. how much dust would it pick up in 365 days?

Answer 1

in 30 days Earth picks up 7.8×10^8kg dust
in one day Earth picks up dust per kg =7.8×10^8\30
= 7.8×10^8\3×10^1
=7.8×10^8-1\3. (a^m÷a^n=a^m-n)
in one day Earth picks up dust per kg =7.8×10^7\3
in 365 day Earth picks up dust per kg=7.8×365×10^7\3
=2847×10^7\3
=949×10^7. or 9490000000kg

Answer 2

Hi friend,

In 30 days earth picks up 7.8*10⁸ kg 
Then in 1 day he will pick up 7.8*10⁸kg/30
In "n" days he will pick up n*amount picked in 1 day.
So in 365 days he will pick up 365*7.8*10⁸/30
                                              =94.9*10⁸
                                              =949*10⁹kg.