Question

A swimming pool is open for 7 1/2 hours a day. The pool keeps one life guard on duty at a time, and each life guard shift is 1 1/2 hours long. How many shift per day?

Answer 1

There are 5 shifts per day

Solution:

Given that, A swimming pool is open for $7\frac{1}{2}$ hours a day

The pool keeps one life guard on duty at a time

Each life guard shift is $1\frac{1}{2}$ hours long

To find: Number of shifts per day

From given,

$\text{ Number of hours } =7\frac{1}{2} = \frac{2 \times 7 + 1}{2} = \frac{15}{2}$

$\text{Each life guard shift }= 1\frac{1}{2} = \frac{3}{2} \text{ hours }$

Therefore, number of shifts per day is found by dividing total number of hours by hours of each life guard shift

$\text{Number of shifts per day } = \frac{\text{Total number of hours}}{\text{each life guard shift }}$

Substituting the values we get,

$\text{Number of shifts per day } = \frac{\frac{15}{2}}{\frac{3}{2}}\\\\\text{Number of shifts per day } = \frac{15}{2} \times \frac{2}{3}\\\\\text{Number of shifts per day } = 5$

Thus there are 5 shifts per day