Question

I need help with this math question I already solved the first question but I don't understand the second.

Answer 1

We can solve this question using cross multiplication,

If the number of students who sleep 6 hours a day increases by, this means we'll have a total of 6 students who sleep 6 hours a day.

We want the ratio to be same: 15%

Then we can write:

$\frac{6}{N}=\frac{15\%}{100\%}$

6 students are the 15%, then N students are the 100%

Now solve for N:

$\begin{gathered} 6·100=15·N \\ \end{gathered}$$N=\frac{600}{15}$$N=40$

The answer is 40 students are expected.

This is a reasonable answer, given that if the number of students who sleep 6 hours doubles, for the rate to remain the same, the total of students must double.