Question 1122711: Out of 13 cows one worth rs 26000 was removed and a horse was included if the average price of animals increased by rs 15000 find the price of horse
Found 2 solutions by Theo, ikleyn:
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! one cow is worth 26000.
with just cows, the average price is 26000
with 12 cows and one horse, the average price is 26000 + 15000 = 41000.
with all cows, then the total price is 13 * 26000 = 338,000
with 12 cows and 1 horse, the total price is 13 * 41000 = 533,000
12 cows at 26000 each is equal to 312,000
the horse must have cost 533,000 minus 312,000 = 221,000
12 cows at 26000 each plus 1 horse at 221,000 = 533,000 / 13 = average price of 41,000 each.
algebraically, you might solve as follows:
with cows only, you get 13 * 26000 / 13 = 26000
with 12 cows plus 1 horse, you get (12 * 26000 + x) / 13 = 41000
x represents the price of the horse.
solve that equations for x as follows:
start with (12 * 26000 + x) / 13 = 41000
multiply both sides of that equation by 13 to get 12 * 26000 + x = 13 * 41000
subtract 12 * 26000 from both sides of that eqution to get x = 13 * 41000 - 12 * 26000.
this results in x = 533,000 - 312,000 = 221,000
that's the price of the horse.
Answer by ikleyn(52879)  (Show Source):
You can put this solution on YOUR website! .
Equation 1: 12 cows + 13-th cow cost together 13*X, where X is the average cost of 13 cows (now unknown).
Equation 2: 12 cows + the horse cost together 13*Y, where Y is the average cost of 13 animals (now unknown).
Subtract equation (1) from equation (2). You will get
the horse price - the 13-th cow price = 13*(Y - X).
In the last equation, you know that Y - X = 15000 (given !) and the 13-th cow price = 26000.
Therefore, the horse price = 26000 + 13*15000 = 221000.
Solved.
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