Amother's age is three less than three times her daughter's age. the sum of their ages is 45. what is the daughter's age?
a) 33
b) 12
c) 42
d) 15

Given:
mother's age = 3x - 3
daughter's age = x
total of their ages = 45

Mother's age + daughter's age = 45
3x - 3 + x = 45
4x = 45 + 3
4x = 48
4x/4 = 48/4
x = 12 daughter's age.  CHOICE B.

mother's age : 3x - 3 = 3(12) - 3 = 36 - 3 = 33

To check:
mother's age + daughter's age = 45
33 + 12 = 45
45 = 45