Question

A lady has 25 paise and 50 paise coin in her purse if in all she has 40 coins totalling rupees 12.50 find the number of coins of each type she has

Answer 1

let the 25 paisa coin be x in numbers,and 50 paisa coin be y
$x + y = 40 \\ \frac{x}{4} + \frac{y}{2} = 12.50 \\ \frac{x + 2y}{4} = 12.50 \\ x + 2y = 50 \\ subtract \: both \: equations \\ - y = - 10 \\ y = 10 \\ x + 10 = 40 \\ x = 30$
25 paisa coins are 30 and 50 paisa coins are 10 in numbers.