so represent the ages as x y and z with each being numbers
x+y+z=21
x times y times z=75
this is really tough for elementary school
one way is to find the factors of 75 or the numbers that add up to 75 and trial and error
use whole numbers becuase this is the world of math so
75=1 times 3 times 5 times 5
possible ages are
3,5,5
1,5,15
1,3,25
add them up
3+5+5=13
1+5+15=21 check
1+3+25=29
their ages are 1, 5 and 15
