SOLUTION: 10 cows or 25 goats can graze a field in 20 days.How long would 12 cows and 15 goats take to graze the same field?

Algebra ->  Average -> SOLUTION: 10 cows or 25 goats can graze a field in 20 days.How long would 12 cows and 15 goats take to graze the same field?      Log On


   



Question 695863: 10 cows or 25 goats can graze a field in 20 days.How long would 12 cows and 15 goats take to graze the same field?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
10 cows or 25 goats can graze a field in 20 days.
From this we can say a field can be grazed in:
200 cow-days
or
500 goat days
:
How long would 12 cows and 15 goats take to graze the same field?
let d = no. of days with the above animals
let the the grazed field = 1
:
%2812d%29%2F200 + %2815d%29%2F500 = 1
Multiply by 1000 to clear the denominators, results:
5(12d) + 2(15d) = 1000
60d + 30d = 1000
90d = 1000
d = 1000/90
d = 11.1 days