Ruksana travelled at 60 km/h while going from point A to point B, and returned via the same route at a different speed. If Ruksana’s overall average speed during the two-way journey was 48 km/h, what was her speed while travelling from B to A?
Answer & explanation
Correct answer: option 2
Average speed = \(\frac{2 × S1 × S2 }{S1 + S2}\)
48 = \(\frac{2 × 60 × S2 }{60 + S2}\)
5 × S2 = 120 + 2 ×S2
3 ×S2 = 120
S2 = 40
So Desired speed is 40 km/h