SOLUTION: Ely is worried about the electricity going out, and he is trying to decide which candles to buy. There are two kinds at the same price. The red ones are 30 cm. long and burn at a

Algebra ->  Average -> SOLUTION: Ely is worried about the electricity going out, and he is trying to decide which candles to buy. There are two kinds at the same price. The red ones are 30 cm. long and burn at a      Log On


   

Question 891367: Ely is worried about the electricity going
out, and he is trying to decide which candles to buy. There are two kinds at the
same price. The red ones are 30 cm. long and burn at an average rate of 5.5 cm
per hour. The white ones are only 19 cm long, but they are thicker and burn at a
rate of 3.3 cm per hour. Both will burn all the way to the bottom.
a. Which candle will burn longer? How much longer? Show how you know.
b. After how many hours will the two candles be the same height? Show two
methods to figure this out.
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Those questions do not seem to be the best ones to answer.

The burn time would be height%2Frate.

CANDLE__________HEIGHT_________RATE(cm/hour)_____TIME(hours)
Red_____________30 cm__________5.5_______________5.46
White___________19 cm__________3.3_______________5.76

Obviously the white, shorter but thicker candle will burn longer. How much longer is 0.76-0.46=highlight%280.30%29 hours longer. About 18 minutes.

Questions in part b are vert poor value.