Mixed grazing rates for goats and sheep Either 4 goats or 6 sheep can graze a field in 50 days. If 2 goats and 9 sheep graze together, in how many days will they finish the field?

Difficulty: Easy

Correct Answer: 25 days

Explanation:


Introduction / Context:
This is a rates-combination problem using equivalent-team times. We find individual animal rates and sum them for the new team.



Given Data / Assumptions:

  • 4 goats in 50 days ⇒ 1 job.
  • 6 sheep in 50 days ⇒ 1 job.
  • Team: 2 goats + 9 sheep.


Concept / Approach:
Compute per-day per-animal rates from the team times, add them, and invert to get time.



Step-by-Step Solution:

Rate(goat) = 1 / (4 * 50) = 1/200 per dayRate(sheep) = 1 / (6 * 50) = 1/300 per dayTeam rate = 2*(1/200) + 9*(1/300) = 1/100 + 3/100 = 1/25 per dayTime = 1 / (1/25) = 25 days


Verification / Alternative check:
If they worked 25 days, they would do 25 * (1/25) = 1 job, confirming correctness.



Why Other Options Are Wrong:
50, 75, 100 days correspond to incorrect combined rates.



Common Pitfalls:
Failing to convert team times into per-animal rates before recombining.



Final Answer:
25 days

More Questions from Time and Work

Discussion & Comments

No comments yet. Be the first to comment!
Join Discussion