Subject: General Aptitude · Chapter: Problems on Numbers · Exam: · Marks: · Difficulty:
A man bought some eggs of which 10\% are rotten. He gives 80\% of the remainder to his neighbors. Now he is left out with 36 eggs. How many eggs he bought? [SSC-CHSL (10 +2) Exam, 2015]
(a)40
(b)100
(c)200
(d)72
Answer
Answer (as printed): C
Explanation
Let the total number of eggs bought be $a$. 10% of eggs are rotten. ∴ Remaining eggs $=a-10\%$ of $a=a-\frac{10a}{100}=\frac{90a}{100}=\frac{9a}{10}$. Man gives 80% of these eggs to his neighbour $=\frac{80}{100}\times\frac{9a}{10}=\frac{72a}{100}$. Remaining eggs $=\frac{9a}{10}-\frac{72a}{100}=\frac{90a-72a}{100}=\frac{18a}{100}=\frac{9a}{50}$. According to the question, $\frac{9a}{50}=36 \Rightarrow 9a=36\times50 \Rightarrow a=\frac{36\times50}{9}=200$. Hence the total number of eggs bought is 200.
Explanation as extracted from the printed page; notation may be imperfect.