SOLUTION: 6 oxen or 8 cows can graze a field in 28 days. How long would 9 oxen and 2 cows take to graze the same field.

Question 415673: 6 oxen or 8 cows can graze a field in 28 days. How long would 9 oxen and 2 cows take to graze the same field.
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
6 oxen or 8 cows can graze a field in 28 days.
How long would 9 oxen and 2 cows take to graze the same field.
:
Here is one way, use "oxen-days" and "cow-days"
:
It takes 6*28 = 168 oxen days to graze the field
or
It takes 8*28 = 224 cow-days to graze the field
:
Let t = time required by 8 oxen, and 2 cows
:
Let the grazed field = 1
:
Each animal will do a fraction of the field, the two fractions = 1
:
t + t = 1
Least common multiple = 672 to clear denominators, multiply eq by this, results:
4(8t) + 3(2t) = 672
32t + 6t = 672
38t = 672
t =
t = 17.7 days, for 8 oxen and 2 cows to graze the field
:
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