Question

four times Bruce's age plus two times Sarah's age equals 84. Bruce's age is also three times Sarah's age. how old is Bruce?

Answer 1

bruce=x
sarah=y

4x+2y=84
x=3y
subsitute
4(3y)+2y=84
12y+2y=84

14y=84
divide both sides by 14
y=6
sarah=6
x=3(y)
x=3(6)
x=18


bruce=18
sarah=6