Question

there are 2 candles of same length and same size. both of them burn at uniform rate. the first one burns in 5 hours and the second burns in 3 hours. both the candles are lit together. after how much time, the length of first is three times that of the other?

Answer 1

Answer:

2.5 Hrs

Step-by-step explanation:

there are 2 candles of same length and same size. both of them burn at uniform rate. the first one burns in 5 hours and the second burns in 3 hours. both the candles are lit together. after how much time, the length of first is three times that of the other?

Let say Length of both Candles = 15L

one Burn in 1 hr = 15L/5  = 3L

Another Burn in 1 hr = 15L/3 = 5L

Let say After X hrs Required conditions are met

one Burn = 3XL    Remaining = 15L - 3XL

second burn = 5XL  Remaining = 15L - 5XL

15L - 3XL = 3(15L - 5XL)

=> 15L - 3XL  = 45L - 15XL

=> 12XL = 30L

=> X = 2.5

After 2.5 Hrs the length of first is three times that of the other