Question

aayan bought as many 25 paise postal stamps as 50 paise stamps and paid ₹ 9 for them. how many stamps of each denomination did he buy

Answer 1

aayan bought 18 (25 paise)stamps and 9 (50 paise) stamps for 9 rupees(900 paise)

Answer 2

let aayan bought x 25 paisa postal tickets and y 50 paisa postal tickets
value of 25 paisa ticket as compare to one Rupee's x/4.
value of 50 paisa ticket as compare to one Rupee's y/2.
total he pay 9 Rupee's
$x = y \\ x - y = 0 \: \: \: \: \: \: eq1\\ \frac{x}{4} + \frac{y}{2} = 9 \\ \frac{x + 2y}{4} = 9 \\ x + 2y = 36 \: \: \: \: \: eq2 \\ subtract \: eq \: 1 \: and \: 2 \\ - 3y = - 36 \\ y = \frac{36}{3} \\ y = 12 \\ x = 12$
aayan purchase 12 25 paisa postal tickets and 12 25 paisa postal tickets