Question

I need help with this please?

Answer 1

SOLUTION

Write out the given information

$\begin{gathered} \text{Initial volume of gas=40litre} \\ \text{percentage of gas lost per day=0.5\%} \\ \text{The percentage remaining will be } \\ 100-0.5=99.5\text{ \%} \end{gathered}$

Then

After each day, the gas will be remaining

$\begin{gathered} \frac{99.5}{100}=0.995 \\ \\ \end{gathered}$

Then, then for one week, we will have

$(0.995)^7$

Hence

The volume of the gas that will be remaining will be

$40(0.995)^7$

Therefore

The volume of gas after one week is 40(0.995)^7

The fourth option is correct (D)