Question

Two candles start burning at the same time. One candle is 15 cm tall and burns at a rate of 5 cm every 6 hours. The other candle is 25 cm tall and burns at a rate of 2 1/2 cm every hour. How tall will the candles be when they first burn down to the same height?

Answer 1

Answer: 10 cm

Explanation:

o=candle one. t=candle two. h=hours

5/6=5/6 cm per hour for o(candle one).

o=15-5h/6

t=25-5h/2

o=t

15-5h/6=25-5h/2

-5h/6=10-5h/2

(-5h/6=10-5h/2)*6

-5h=60-5h*6/2

-5h=60-30h/2

-5h=60-15h

10h=60

h=6

o=15-5h/6

o=15-5(6)/6

o=15-5

o=10 cm