A trader bought two articles for Rs. 490. He sold one at a loss of 20% and the other at a profit of 16%. If the selling price of both the articles is same, then the cost price (in Rs.) of the article sold at 20% loss will be:
A. 300
B. 280
C. 310
D. 290
SSC CGL 2022 13 August 2021 Shift 1
Solution:
Let the articles be A1 and A2 sold at 20% loss and 16% profit respectively.
Let the Cost Price (CP) of the A1 for the trader be = x
Then the Cost Price (CP) of the A2 for the trader will be = 490 - x
It is given that the Selling Price (SP) of A1 and A2 are the same.
Let the Selling Price be = y
It is given that,
On sale of A1, Loss % = 20%
On sale of A2, Profit % = 16%
We know that,
Loss % = ((CP - SP)/CP) * 100 .......(1)
Profit % = ((SP - CP)/CP) * 100 ........(2)
Putting values in eq. 1 for A1 and in eq. 2 for A2
20 = ((x - y)/x) * 100 .......(3)
16 = ((y - (490 - x))/(490 - x)) * 100 ....(4)
From eq. 3, we get
20/100 = 1 - y/x
y/x = 1 - 20/100
y/x = 80/100
y = 4x/5 ....(6)
Substitute eq. (5) in eq. (4)
16 = ((4x/5 - (490 - x))/(490 - x)) * 100
16/100 = (4x/5)/(490 - x) - 1
4x/(5(490 - x)) = 16/100 + 1
4x/(5(490 - x)) = 116/100
4x/(5(490 - x)) = 29/25
100x = 29 * 5 * (490 - x)
100x = 71050 - 145x
245x = 71050
x = 71050/245
x = 290.
Hence, (d) is the correct answer.
Percentage shortcuts for fast calculation.