Question

A man buys postage stamps of 25 paise and 50 paise denominations for Rs. 10. He buys 25 stamps in all. Find the number of 25 paise and 50 paise stamps he purchased​

Answer 1

$\large\underline{\sf{Given- }}$

A man buys postage stamps of 25 paise and 50 paise denominations for Rs. 10.

He buys 25 stamps in all.

$\large\underline{\sf{To\:Find - }}$

The number of 25 paise and 50 paise stamps he purchased.

$\large\underline{\sf{Solution-}}$

Let us assume that

Number of 25 paisa coins be x

Number of 50 paisa coins be y.

According to statement,

A man buys postage stamps of 25 paise and 50 paise denominations for Rs. 10.

Amount for 25 paisa postage stamps = 25x

Amount for 50 paisa postage stamps = 50y

Total amount = Rs 10 = 10 × 100 = 1000 paisa.

$\rm :\longmapsto\:25x + 50y = 1000$

$\rm :\longmapsto\:25(x + 2y)= 1000$

$\rm :\longmapsto\:x + 2y= 40 - - - (1)$

According to second condition,

He buys 25 stamps in all.

$\rm :\longmapsto\:x + y = 25 - - - (2)$

On Subtracting equation (2) from equation (1), we get

$\rm :\longmapsto\:y = 15 - - - (3)$

On substituting the value of y in equation (2), we get

$\rm :\longmapsto\:x + 15 = 25$

$\rm :\longmapsto\:x = 25 - 15$

$\rm :\longmapsto\:x = 10$

Hence,

Number of 25 paisa coins be 10

Number of 50 paisa coins be 15