6 goats or 8 sheeps can graze a field in 50 days. 8 goats and 6 sheeps can graze the field in:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 24 days
Let the work done = 1 field.
If 6 goats graze it in 50 days:
$6G×50=1⇒G=\frac{1}{300}$ (field per day)
Similarly, 8 sheep graze it in 50 days:
$8S×50=1⇒S=\frac{1}{400}$ (field per day)
Rate for 8 goats and 6 sheep
Work rate = $8G+6S$
Substitute values:
$8\left(\frac{1}{300}\right) + 6\left(\frac{1}{400}\right)$
Find common denominator = 1200:
$=\frac{8 \times 4}{1200} + \frac{6 \times 3}{1200}$
$=\frac{32 + 18}{1200} = \frac{50}{1200} = \frac{1}{24}$
$\text{Time taken} = \frac{\text{work}}{\text{rate}}$
Time = $\frac{1}{1/24} = 24$ days