question_answer

Two candles of the same height are lighted at the same time. The first is consumed in 3 hours and the second in 1 hour. Assuming that each candle bums at a constant rate. in how many hours after being lighted, the ratio between the first and second candles become \[2:1\]

A)  48 minutes

B)  1 hours / 36 minutes

C)  36 minutes

D)  60 minutes

Correct Answer: C

Solution :

 Take L.C.M \[(3,1)=3\,hr\] (Each candle bums at constant Rate)             \[3-t:3-3t\] \[\frac{3-t}{3-3t}=\frac{2}{1}\] \[3-t=6-6t\] \[5t=3\] \[t=\frac{3}{5}\times 60\] \[\therefore \]    \[\]