A farmer had d animals, all of which the farmer bought for the same price. The farmer decided to sell the animals. 20 of the animals were sold at a profit of 10% each while the rest were sold at a loss of 20% each. Overall, the farmer made neither a profit nor a loss. Which of the following is equal to d?	Choose one
A) 24  B) 26  C) 28  D) 30  E) 36
Let P be the price the farmer paid for each animal.   The total profit on the 20 animals is 20*0.1*P.   The total loss on the other (d-20) animals is (d-20)*0.2*P.   (d-20)*0.2*P = 20*0.1*P   0.2*d = 2 + 4   d = 30   The answer is 30.
<result>D</result>
A farmer had d animals, all of which the farmer bought for the same price. The farmer decided to sell the animals. 20 of the animals were sold at a profit of 10% each while the rest were sold at a loss of 20% each. Overall, the farmer made neither a profit nor a loss. Which of the following is equal to d?