a sum of 500 is in the form of denominations of 5 and 10. if the total number of notes is 90, find the number of notes of each type.

Let x be the number of notes of denomination Rs5

Let y be the number of notes of denomination Rs10

we know that the total amount is Rs500 which means 5 times the number of notes of denom Rs5 + 10 times the number of notes of denomination Rs 10 equals 500

ie. 5x+10y=500

Also total number of notes is 90 ie x+y=90

hence x=90-y

5*(90-y)+10y=500

450-5y+10y=500

5y=500-450

5y=50

y=50/5

y=10

x=90-y=90-10=80

hence 10 notes of Rs10 and 80 notes of Rs5

Solution:

Let us assume that the total no. of Rs. 10 denomination notes be X., then the Rs. 5 denomination notes will be (90 - X).

From the problem the equation we get:

10 * X + 5 (90 - X) = 500

10x + 450 - 5X = 500

5X = 500 - 450 = 50

X = 50 / 5 = 10.

So the Rs. 10 denominations notes are 10 Nos. and the Rs. 5 denomination notes are (90 - 10) = 80 nos.

Ans: Rs. 5 - 80 Nos Rs. 10 - 10 Nos.