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Question

Answers

$\left( a \right)$ 12

$\left( b \right)$ 16

$\left( c \right)$ 20

$\left( d \right)$ 18

Answer
Verified

Given data:

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

Total number of postage stamps he buys are 28.

And the total amount he spent is Rs. 10

As we all know that 1 Rs = 100 paise.

So, 10 Rs. = 1000 paise.

Now, let the number of postage stamps of denominations 25 paise be X.

So the number of postage stamps of denominations 50 paise are (28 – X) as the total number of postage stamps are 28.

Now the sum of the multiplication of respective postage stamps with their respective cost is equal to the total amount he spent in paise.

So convert the above information into equation we have,

$ \Rightarrow 25X + 50\left( {28 - X} \right) = 1000$

Now simplify this equation we have,

$ \Rightarrow 25X + 1400 - 50X = 1000$

$ \Rightarrow 25X = 1400 - 1000 = 400$

$ \Rightarrow X = \dfrac{{400}}{{25}} = 16$

So there are 16 postage stamps of denominations 25 paise.

And the number of postage stamps of denominations 50 paise = (28 – X) = (28 – 16) = 12

So this is the required answer.