Sure:
90 year old parents : 60 year old children (had kids at 30; very reasonable)
60 year old parents : 40 year old children (had kids at 20; unlikly but possible)
45 year old parents : 30 year old children (had kids at 15; very unlikly but not impossible)
The question is related to trigonometric ratio rule .
In the given diagram, there is a right angle triangle, with adjacent =57, and the unknown side is y. Given angle measurement is 39 .
To find the measurement of y, we will use tan rule which is


y = 57 tan 39 = 46.2
The answer to number 9 would be 43.
Since it tells you that there is a straight angle that would equal 180. So I added up 61 30 and 46. I got 137. Then subtracted 137 from 180 and got 43.