A house is sold by A to B at a profit of 10% and by B to C at a loss of 10%. If C pays $980,100 for it, what was the cost of the house for A?
The Usual Method
Let the cost of the house to A be $‘x’.
Hence, cost price to B = 1.1x
And cost price to C =
Estimated Time to arrive at the answer = 45 seconds.
Assume that the cost price to A = $100
Hence, cost price to B = $110
Hence, cost price to C = $99
Note that cost price to C < cost price to A.
Thus, 980,100 < cost price to A.
This eliminates options ‘1’, ‘2’ and ‘3’.
Also note that, if the cost to A = 100; cost to C = 99, thus if cost to A = $1,000,000; cost to C = $990,000, but actual cost to C = $980,100. Thus option ‘4’ is the answer.
Estimated Time to arrive at the answer = 15 seconds.