The question asks for the ratio of the present ages of Z and P. We are given information about their ages ten years ago.
To find the present ages, we add 10 years to their ages from ten years ago.
The ratio of the respective present ages of Z and P is calculated as:
Z's Present Age : P's Present Age
$28 : 36$
To simplify the ratio, find the greatest common divisor (GCD) of 28 and 36, which is 4.
Divide both numbers by 4:
$\frac{28}{4} : \frac{36}{4}$
$7 : 9$
The ratio of the respective ages of Z and P at present is 7:9.