Same chapter4 marksDifficulty: Hard
A boat covers 24 km downstream in 2 hours and returns upstream in 3 hours. Find the speed of the boat in still water and the speed of the current.
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4 marksDifficulty: Hard
Five years ago a father was seven times as old as his son. Five years hence the father will be three times as old as his son. Find their present ages.
Original Khojo Papers practice question — not from a past board paper.
Answer
The father is 40 and the son is 10.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Let the present ages be f and s. Then f − 5 = 7(s − 5) and f + 5 = 3(s + 5). Subtracting gives 10 = 3s + 15 − 7s + 35, that is 4s = 40, so s = 10 and f = 40.
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