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the sum of robin and brunos age is 45.seven years ago robin was 16 yaers more than one yhalf as old as brunowas the.how old is bruno?

Sagot :

Present ages:
Robin: x
Bruno: y

x + y = 45
      y = 45 - x  (Bruno's age)

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

Equation:
x - 7 =  ¹/₂ (38 - x) + 16

x - 7 = 19 - x/2 + 16

x + x/2 = 19 + 16 + 7

LCD: 2

(2)x + (2) x/2  = 42 (2)

2x + x = 84

3x = 84

3x/3 = 84/3

x = 28

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

ANSWER:  Bruno is 17 years old

Ages Seven years ago:
Robin: 28 - 7 = 21 years old
Bruno:  17 - 7 = 10 years old

Seven years ago, Robin's age was 16 years more than 1/2 of Bruno's.
21 = 1/2 (10) + 16
21 = 5 + 16
21 = 21