Bunuel
The percentage profits on three articles X, Y, and Z is 10%, 20% and 25% and the ratio of their cost price is 1:2:4. Also, the ratio of the number of articles sold of X, Y and Z is 2:5:2. The overall profit percentage is:
A. 15
B. 17
C. 19
D. 21
E. 23
Solution: The ratio of CP is 1:2:4. So, let the CPs be \(x, 2x\) and \(4x\).
The ratio of the number of articles is 2:5:2. So, let the number of articles be \(2y, 5y\) and \(2y\).
Thus, total CPs are \(x\times 2y=2xy, 2x\times 5y=10xy\) and \(4x\times 2y=8xy\)
We know the percentage profit is 10%, 20% and 25%.
So, profit on each articles are:
\(P_1=40\)% of \(2xy=\frac{xy}{2}\)
\(P_2=20\)% of \(10xy=2xy\)
\(P_3=25\)% of \(8xy=2xy\)
Thus, total profit \(= \frac{xy}{2}+2xy+2xy=\frac{21xy}{5}\)
Total CP \(= 2xy+10xy+8xy=20xy\)
Profit percent \(= \frac{4.2xy}{20xy}\times 100=21\)%
Hence the right answer is
Option D.