Robert can eat a 20 kg bag of potatoes in 10 days. He and his wife Jane can eat the same bag in 7 days. How many days does it take Jane to eat a 20 kg bag of potattoes by herself?
anyways, is the answer 5?
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Advanced Arithmetics
Source: Beat The GMAT — Data Sufficiency |
Hi,
Robert eats 20kilos in 10 days ->2kg/day
Robert and Jane eat the same in 7 days ->20/7 kg/day
So, Jane eats (20/7)-2 = 6/7kg/day
So, Jane takes 20/(6/7) = 70/3 days.
Robert eats 20kilos in 10 days ->2kg/day
Robert and Jane eat the same in 7 days ->20/7 kg/day
So, Jane eats (20/7)-2 = 6/7kg/day
So, Jane takes 20/(6/7) = 70/3 days.
Cheers!
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The weight of the bag is irrelevant. We can plug in any number for the weight of the bag.one of many wrote:Robert can eat a 20 kg bag of potatoes in 10 days. He and his wife Jane can eat the same bag in 7 days. How many days does it take Jane to eat a 20 kg bag of potattoes by herself?
Let bag = 70 kg.
Rate for Robert = w/t = 70/10 = 7 kg. per day.
Combined rate for Robert+Jane = w/t = 70/7 = 10 kg. per day.
Thus, rate for Jane alone = rate for Robert+Jane - rate for Robert alone = 10-7 = 3 kg. per day.
Time for Jane alone = w/r = 70/3 days.
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As a tutor, I don't simply teach you how I would approach problems.
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