Same chapter4 marksDifficulty: Hard
The sum of the ages of a father and his son is 45 years and the product of their ages is 350. Find their present ages.
Quadratic Equations
4 marksDifficulty: Hard
A train travels 360 km at a uniform speed. Had the speed been 5 km/h more, it would have taken one hour less for the journey. Find the speed of the train.
Original Khojo Papers practice question — not from a past board paper.
Answer
40 km/h
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
If the speed is x km/h then 360/x − 360/(x + 5) = 1. Multiplying out gives 360 × 5 = x(x + 5), so x2 + 5x − 1800 = 0. The discriminant is 25 + 7200 = 7225 = 852, so x = (−5 + 85)/2 = 40. The negative root is rejected because a speed cannot be negative.
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