Hourglasses
You have two hourglasses: A 7 minute one and an 11 minute one. Using just these 2 hourglasses, accurately time 15 minutes. A more wordy version of this - A baker has only 2 timers that can measure 7 minutes and 11 minutes. How can he set a timer for 15 minutes to bake a cookie?
Level: Easy (introduction)
posted by Karthik Nagaraj at
11:59 PM
2 Comments:
start the 7 & 11 hour glass
once the 7 runs out tumble both -> we measured 7 mins
once the 11 mins runs out tumble the 7 min -> we have measured 4 mins
once the 7 mins runs out you are done -> we have measured 4 mins
that is 15 mins in total
Vidya,
Thats correct! Excellent
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