Grazing cows riddle
Algebra
Level
pending
It was part of Newton's inspiration.
A field of grass needs 5 cows to finish in 8 days, 7 cows to finish in 4 days. So, how many cows are needed to finish the grass in 2 days?
Details: Grass grows every now and then!
The answer is 11.
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1 solution
U need to know how fast the grass grows every day. Assume every cow eats 1 unit of grass every day. Speed of growing=(5×8-7×4)÷(8-4) =3 unit per day The actual amount of grass in field=7×4-4×3 =16 unit The amount of grass in 2 days=16+3×2 =22 unit So it requires 22/2=11 cows to graze!!!