Question

A younger kid does not understand and I don’t know either. Thanks

Answer 1

Think of the amount 3/5 of an hour.
What do you multiply 3/5 hour by to get 1 hour?
You multiply 3/5 by its reciprocal, 5/3, to get 1, since 3/5 * 5/3 = 15/15 = 1.

Since you multiply the time by 5/3 to get 1 hour, you also multiply the fraction of the allowance by 5/3.

3/4 of the allowance * 5/3 = 15/12 of the allowance = 5/4 of the allowance.

---------------------------------------------------------------------------------------------------

Here is another way of thinking of this.
Turn this into a unit rate problem.

3/4 allowance for 3/5 of an hour is what unit rate of allowance per hour?
Divide 3/4 allowance per 3/5 hour.

$\dfrac{\frac{3}{4}~allowance}{\frac{3}{5}~hour} =$

$= \dfrac{\frac{3}{4}}{\frac{3}{5}}\dfrac{allowance}{hour}$

$= \dfrac{3}{4} \times \dfrac{5}{3}\dfrac{allowance}{hour}$

$= \dfrac{3 \times 5}{4 \times 3} \dfrac{allowance}{hour}$

$= \dfrac{5}{4} \dfrac{allowance}{hour}$

The unit rate is 5/4 of the allowance per hour.