Intelligent Math Puzzle – Challenge 91

Challenge:

Mrs. Walters has 61 candles. She burns one candle every day and always makes one new one from the remaining wax of seven burnt candles. After how many days she needs to buy new candles?

A- 62

B- 68

C- 69

D- 70

E- 71

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Mrs. Walters burns one candle every day and she can make a new one from the remaining wax of seven burnt candles. After 56 days, Mrs. Walters can make 8 new candles. (56 ÷ 7 = 8)
So, she has 13 candles now. After seven days, she burns 7 candles and makes another candle. So, she has 7 candles now. She can burn these 7 candles in 7 days and make a new candle after that for another day.
Therefore, she needs to buy new candles after 71 days:
56 + 7 + 7 + 1 = 71

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