Two individuals, A and B, rent a pasture together. A has 18 horses that they graze for 4 months. B grazes 24 cows for 6 months and 36 sheep for 4 months. The following relationships are given: - 3 horses are equivalent to 6 cows, - 4 cows are equivalent to 8 sheep. What amount of rent should A pay ?
- (a)2⁄5
- (b)3⁄5
- (c)4⁄5
- (d)1⁄5
Answer
Why
Correct — A. Put every animal in one unit, sheep.
3 horses = 6 cows, so 1 horse = 2 cows
4 cows = 8 sheep, so 1 cow = 2 sheep
Chain them: 1 horse = 2 × 2 = 4 sheep
A: 18 × 4 = 72 horse-months = 72 × 4 = 288 sheep-months
B, cows: 24 × 6 = 144 cow-months = 144 × 2 = 288 sheep-months
B, sheep: 36 × 4 = 144 sheep-months
Add B's: 288 + 144 = 432
A : B = 288 : 432 = 2 : 3
A pays 2 ⁄ (2 + 3) = 2⁄5 of the rent → option (a)
Why the others are wrong
- (b)3⁄5 — 3⁄5 is B's share, not A's. The grazing splits 288 : 432 = 2 : 3, and B's cows and sheep take the larger 3 parts of 5.
- (c)4⁄5 — 4⁄5 would mean A grazed four times as much as B. In sheep-months A has 288 and B 432, so A grazed less and pays under half.
- (d)1⁄5 — 1⁄5 would mean B grazed four times as much as A. B's 432 sheep-months are only 1.5 times A's 288.
Concept
Rent on a shared pasture works like capital × time in a partnership: each tenant pays in proportion to animals × months grazed. The animals must first be in one unit, because here one horse grazes as much as four sheep.
Chain the equivalences, horse to cow and cow to sheep, and convert to the smallest animal so the numbers stay whole. Then split the rent in the ratio of the totals.
The stem asks 'What amount of rent should A pay' but never gives a total rent, and every option is a fraction. Read it as A's fraction of the whole rent.
Key facts
- Pasture rent is shared in the ratio of animals × months, with all animals in one unit.
- Here 1 horse = 2 cows = 4 sheep, from 3 horses = 6 cows and 4 cows = 8 sheep.
- A : B = 288 : 432 = 2 : 3, so A pays 2⁄5 and B pays 3⁄5.
Study next
Common traps
- Leaving A's horses unconverted: 72 against B's 432 sheep-months gives A only 1⁄7.
- Converting the wrong way: 1 horse = 2 cows means a horse counts double, so horse-months are multiplied, not divided.
- Choosing 3⁄5, which is B's share.
The same horse–cow–sheep conversion is asked at 12 Sep 2025, 16:00, Quant Q.6, where A's portion is 8⁄17, and a cow–sheep version at 12 Sep 2025, 16:00, Quant Q.7 gives 44⁄89.
Related PYQs
No directly related past PYQ was found.