Question

Cindy's age is 5 years less than three times Roy's age. If Cindy is 16 years old, how old is Roy?

A. 4
B. 5
C. 7
D. 15

Answer 1

Work backwards. Cindy is 16 which is five years LESS. So do the opposite of subtract and add 16 and 5.

16+5=21

Then the problem says three TIMES less. The opposite of multiply is divide. So divide 21 and 3.

21 / 3= 7

Therefore the answer is C

Answer 2

let cindy’s age = a
let Roys age = r
cindy’s age is 5 less than 3 times roy’s age, therefore, a= (3•r) - 5
a + 5 = 3r
r = (a + 5)/3
it is known cindy is 16, therefore sub a = 16
r = ((16) +5)/3
r = 21/3
r = 7
therefore rory is 7 years of age