Question
Riya and Tanya were assigned two exhibition stalls such
that the distances from their homes are 36 km and 48 km respectively. They both left their house at the same time and reached their stalls by 9 A.M. One day the stalls were switched, and Riya started 20 minutes earlier than Tanya to reach her new stall on time. Find the speed of Riya.Solution
ATQ,
Distance covered by Riya and Tanya = 36 km and 48 km, respectively Since both reached on time Ratio of speeds of Riya and Tanya = 36 : 48 = 3 : 4 Let the speeds of Riya and Tanya be 3x km/hr and 4x km/hr respectively Time taken by Riya after switch = 48 / 3x Time taken by Tanya after switch = 36 / 4x According to the question, (48 / 3x) – (36 / 4x) = 20 / 60 ⇒ x = 12 Therefore, speed of Riya = 3x = 36 km/hr
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