| 2010-08-22 12:01:52 |
Pavel Mikhalev |
description |
Binary package hint: gbrainy
"John's age is nowadays 2 times his son's age. 18 years ago, John was 5 times older than his son. How old is John's son nowadays?"
Gbrainy says that correct answer is 40 (on the attached screenshot), but it isn't true. If nowadays John's son is 40, then John is 80 (2x). 18 years ago John's son was 22 and John was 62 (2.8x, which is incorrect statement).
Puzzle can be solved, using simple equation. Let son's age nowadays will be x, than John's age will be 2*x. 18 years ago: 2*x-18=5*(x-18). From this x=24. Nowadays, John's son is 24 and John himself is 48 (2x), 18 years ago John's son was 6 and John was 30 (5x).
Correct answer must be 24, not 40. |
Binary package hint: gbrainy
Affected version: 1.50
"John's age is nowadays 2 times his son's age. 18 years ago, John was 5 times older than his son. How old is John's son nowadays?"
Gbrainy says that correct answer is 40 (on the attached screenshot), but it isn't true. If nowadays John's son is 40, then John is 80 (2x). 18 years ago John's son was 22 and John was 62 (2.8x, which is incorrect statement).
Puzzle can be solved, using simple equation. Let son's age nowadays will be x, than John's age will be 2*x. 18 years ago: 2*x-18=5*(x-18). From this x=24. Nowadays, John's son is 24 and John himself is 48 (2x), 18 years ago John's son was 6 and John was 30 (5x).
Correct answer must be 24, not 40.
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