Question

a man purchased 47 stamps of 20p and 25 p for rs 10. find the number of each types of stamps

Answer 1

Let x of 20p
so, 47-x of 25p

total rs. 10 = 1000p = 20x +25(47-x) p
so, 1000= 20x + 1175 -25x
or, 1000= 1175-5x
so, 1175-1000=5x
so, 175=5x
or, x=175/5
so, x=35
So, 35 20p stamps and 12 25p stamps .

Thanks.

Answer 2

Answer:

Let the number of stamps of 20p and 25p be x and y respectively. Then as per the question x + y = 47 …….(i) 0.20x + 0.25y = 10 4x + 5y = 200 …….(ii) From (i), we get y = 47 – x Now, substituting y = 47 – x in (ii), we have 4x + 5(47 – x) = 200 ⇒ 4x – 5x + 235 = 200 ⇒ x = 235 – 200 = 35 Putting x = 35 in (i), we get 35 + y = 47 ⇒ y = 47 – 35 = 12 Hence, the number of 20p stamps and 25p stamps are 35 and 12 respectively.