Problem: One-fifth ($\frac{1}{5}$) of the product made by a company is defective. Four-fifth($\frac{4}{5}$) of the defectives are rejected and one-twenty ($\frac{1}{20}$) of the good products is rejected by mistake. If all the products not rejected are sold, what parentages of the products sold by the company are defective?
View all: BANGLADESH RURAL DEVELOPMENT BOARD | WRITTEN QUESTION SOLVE(MATH) | 2004
Correct Answer: 5%
Explanation:
Defective products =$\frac{1}{5}$
Hence Good products = (I -$\frac{1}{5}$) =$\frac{4}{5}$
Rejected of good products =$\frac{4}{5}$ of $\frac{1}{20}$= $\frac{1}{25}$
Rejected of defective products = $\frac{1}{5}$ of $\frac{4}{5}$ = $\frac{4}{25}$
Total rejected products = $\frac{1}{25}$+ $\frac{4}{5}$ = $\frac{1}{25}$
Sold of defective products = $\frac{1}{5}$- $\frac{4}{25}$ = $\frac{1}{25}$
Total rejected products =1 — $\frac{1}{5}$ = $\frac{4}{5}$
Among $\frac{4}{5}$ sold products defective = $\frac{1}{25}$
Among 100 sold products defective = $\frac{100 \cdot 5}{25 \cdot 4}$= 5%
