Question

Mr. Barclay sold goods for $21 and lost a percent equal to the number of dollars he paid for the goods. How much did the goods cost him?

A $70
B $55
C $40
D $95

Please show step by step.

Answer 1

option: A($70)

Explanation:

We are given Selling Price(S.P.) of the goods=$21

Let the cost price(C.P.) of the goods be denoted by 'x'.

Also we are given that the loss percentage is equal to the C.P.

i.e.

`loss\%=(CP-SP)/(CP) * 100`

`CP=(CP-21)/(CP)* 100`

`x=(x-21)/(x)* 100`

`x^(2)=100x-2100\\ \\x^(2)-100x+2100=0\\\\x^(2)-70x-30x+2100=0\\ \\x(x-70)-30(x-70)=0\\\\(x-70)(x-30)=0`

This means that x=70 or x=30

Hence from the options given we could say that the cost price of goods is $70.

Hence option A is correct.