Question

A man buys postage stamps of denominations $25$ paise and $50$ paise for Rs $10$. He buys $28$ stamps in total. Find the number of $25$ paise stamps bought by him.

• A. $12$
• B. $16$
• C. $20$
• D. $18$

Answer 1

Answer: (B)

$16$

Let the man buys x 25 paisa stamps and y 50 paisa stamps. Then
$x+y=28$ .........(1)
and $0.25x+0.5y=10$
or $\frac{1}{4}x+\frac{1}{2}y=10$
or $\frac{x+2y}{4}=10$
$x+y=40$ .........(2)
Subtract equation (1) from equation (2)
$x+2y=40$
$+x+y=28$
$\underset{–}{(-)(-)(-)}$
$y=12$
$\therefore x=28-12=16$