Question

you are given a match-box and two candles of equal size, which can burn 1 hour each. you have to measure 90 minutes with these candles. (there is no scale or clock). how do you do?

Answer 1

first light the first candle. meanwhile cut the second candle into halves. At the instance of it burning out, light the second candle .when the half too burns out 90 minutes would have elapsed.