Question

In 15 days, the earth picks up $1.2\times {10}^8$ kg of dust from the atmosphere. In how many days it will pick up $4.8\times {10}^8$ kg of dust ?

Answer 1

Dust of $1.2\times {10}^8$ kg is picked up in 15 days
Let the dust of $4.8\times {10}^8$ will be picked up in x days
Therefore.
$\begin{array}{ccc}\text{Dust (in kg)}& 1.2\times {10}^8& 4.8\times {10}^8\\ \text{Days}& 15& x\end{array}$
$\therefore \frac{1.2\times {10}^8}{4.8\times {10}^8}=\frac{4.8\times {10}^8}{x}\left(constant\right)\Rightarrow x\times 1.2\times {10}^8=4.8\times {10}^8\times 15\Rightarrow x=\frac{4.8\times {10}^8\times 15}{1.2\times {10}^8}=\frac{4\times {10}^8\times 15}{{10}^8}=60$
$\therefore$ Days = 60