Bunuel
Anna has six pets and plans to give each one a treat. The treats consist of two identical apple slices, along with one banana, one carrot, one mango, and one pear. Her rabbit refuses to eat the mango, and her parrot refuses to eat the banana. In how many distinct ways can she distribute the treats among the pets?
(A) 96
(B) 240
(C) 252
(D) 288
(E) 300
GMAT Club Official Explanation:
Step 1: Total arrangements without restrictionsThe number of ways to distribute the treats A, A, B, C, M, and P among six pets without any restriction is 6!/2! =
360.
Step 2: Invalid cases where the rabbit gets mango or the parrot gets bananaWe now count the number of invalid cases where the rabbit gets mango or the parrot gets banana.
Fix mango to the rabbit. The remaining 5 items, A, A, B, C, and P, can be assigned to the other 5 pets (including the parrot) in 5!/2! = 60 ways.
Fix banana to the parrot. The remaining 5 items, A, A, C, M, and P, can be assigned to the other 5 pets (including the rabbit) in 5!/2! = 60 ways.
However, both cases above include the overlap where the rabbit gets mango and the parrot gets banana. To avoid double-counting, we subtract those. Fix both: mango to the rabbit and banana to the parrot. The remaining 4 items, A, A, C, and P, can be assigned to the other 4 pets in 4!/2! = 12 ways.
This makes the number of invalid cases equal to 60 + 60 - 12 =
108.
Step 3: Subtract invalid cases from totalTherefore, valid cases = total arrangements - invalid cases = 360 - 108 = 252.
Answer: C.