Answer:
first group = 33
second = 15
Step-by-step explanation:
Let size of second group = x
size of the first group = 3x - 12
x + 3x - 12 = 48
4x - 12 = 48
collect like terms
4x = 48 + 12
4x = 60
x = 15
Substitute for x in the equation for size of the first group
3(15) - 12 = 33
