heshamelaziry wrote:Today Bill is 13 times as old as Pete. In 9 yeasr Bill will be 4 times as old as Pete. How old will Pete be 2 years from today ?
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OA is C I would like to know why when i do this it does not work:
B + 9 = 4(13P + 9) ----> 13P + 9 = 52P + 36 DOES NOT WORK !
not sure how this ended up in the data sufficiency forum, but here goes anyway:
1st equation: B = 13P
2nd equation: B + 9 = 4(P + 9)
Question: what's P + 2?
Subbing B=13P into the 2nd equation:
13P + 9 = 4P + 36
9P = 27
P = 3
and answering the question:
P + 2 = 3 + 2 = 5
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Your mistake is that instead of using P for Pete's age in the 2nd equation, you used 13P (13 times Pete's age).
