Brain Teasers
Mad Ade's Cows
Mad Ade has a field of grass that grows equally thick and in a uniform rate. It would take 70 cows 24 days to eat all the grass, or it would take 30 cows 60 days to eat the grass. Unfortunately Mad Ade has only got enough cows to clear the field in 96 days.
How many cows has Mad Ade got?
How many cows has Mad Ade got?
Answer
Mad Ade has 20 cows.Assume one cow does one unit of work in one day. In the first case with 70 cows, total units of work done = 70x24 = 1680.
In the second case with 30 cows, total units of work done = 30x60 = 1800.
So, in 36 days, the grass has grown = 1800-1680 = 120 units of work.
So, in 36 more days, i.e. 96 days, total units of work required = 1800 + 120 = 1920.
No. of cows required = 1920/96 = 20.
Hide Answer Show Answer
What Next?
View a Similar Brain Teaser...
If you become a registered user you can vote on this brain teaser, keep track of which ones you have seen, and even make your own.
Solve a Puzzle
Comments hidden to avoid spoilers.
Follow Braingle!