My friend Charles works in a post office and he sells stamps. One day a man walked in and slamming seventy five rupees on the counter requested,

"Please give me some 2 rupees stamps, six times as many one rupee stamps, and for the rest of the amount make up some 5 rupee stamps."

Charles thought for a few moments and finally she handed over the exact fulfilment of the order to the man.

How did he do it and how many stamps of each type did he give to the man ?

Let TR=x
Let OR=6x
Let FR=y, where TR is the total amount of 2-rupee stamps bought, OR is the total amount of 1-rupee stamps bought, and FR is the total amount of 5-rupee stamps bought.

Hence the equation,

2(x) + 1(6x) + 5y = 75, which yields,

y = (75 - 8x)/5, which says the number of 5 rupee stamps must be divisible by 5. The only value of x that would satisfy this condition would be when x=5.

Substituting in, we get y= (75-40)5, which is 7.
So Charles gave him 7 5-rupee stamps, totaling 35 rupees. Since x=5, then he gave him 6x one rupee stamps (30 1-rupee stamps) totalling 30 rupees.
He also gave him x 2-rupee stamps (5 2-rupee stamps) totalling 10 rupees, all of which adds up to 75 rupees.

So,

7 5-rupee stamps
30 1-rupee stamps
5 2-rupee stamps

Posted by Marc on 2003-03-09 08:16:21