Question

There are some people in a cinema.

Answer 1

Answer:

$Adults = 510$

Step-by-step explanation:

Given

$Children = \frac{3}{5}$

$Girls:Boys = 2 : 7$

$Girls = 170$

Required

Determine the number of adults

First, we need to calculate the number of children

$Girls:Boys = 2 : 7$

Given that: $Girls = 170$

Substitute 170 for Girls in $Girls:Boys = 2 : 7$

$170 : Boys = 2 : 7$

Convert to fraction

$\frac{170}{Boys} = \frac{2}{7}$

Cross Multiply

$Boys * 2 = 170 * 7$

Divide both sides by 2

$Boys = \frac{170 * 7}{2}$

$Boys = \frac{1190}{2}$

$Boys = 595$

So, the number of children are:

$Children = Boys + Girls$

$Children = 595 + 170$

$Children = 765$

Next, we calculate the number of people in the cinema.

$Children = \frac{3}{5} * People$

Substitute 765 for Children

$765 = \frac{3}{5} * People$

Make People the subject.

$People = \frac{765 * 5}{3}$

$People = \frac{3825}{3}$

$People = 1275$

If 3/5 are children, then 2/5 are adults.

So:

$Adults = \frac{2}{5} * 1275$

$Adults = \frac{2* 1275}{5}$

$Adults = \frac{2550}{5}$

$Adults = 510$