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The sum of robin's age and bruno's age is 45. Seven years ago robin was 16 years more than one-half as old as bruno was then. How old is robin now?

Sagot :

i'm not really sure if my answer is correct but i think the answer is 23 I guess :)
~hope it helped :)
Present ages:
Robin: x
Bruno: y

x + y = 45
      y = 45 - x

Ages seven years ago:
Robin: x - 7
Bruno:  45 - x - 7   or    38-x

Equation:
x - 7 = ¹/₂ (38-x) + 16
x  =  19 - ¹/₂ x + 16 + 7
x + ¹/₂ x = 19 + 16 + 7
x + ¹/₂ x = 42

LCD: 2
(2)x + (2) ¹/₂ x = (2) 42
2x + x = 84
3x = 84
3x/3 = 84/3
x = 28

ANSWER:  Robin is 28 years old now.

Present ages:
Robin: x = 28 years old
Bruno: 45 - x = 45 - 28 = 17 years old

Check:
28 + 17 = 45
45 = 45   √