Question

A sum of Rs. 500 is in the form of denominations of Rs. 10 and Rs. 20. If total number of notes are 35, find the number of notes of each denomination.​

Answer 1

Answer: 20 of banknotes, denomination of Rs. 10 and 15 of banknotes, denomination of Rs. 20.

Explanation:

Let the number of banknotes, denomination of Rs. 10 will be equal to x,

and the number of banknotes, denomination of Rs. 20 will be equal to y.

Hence;
`\left \{ {{x+y=35\ \ \ \ } \atop :10 \ \ } \right. \ \ \ \ \left \{ {{x+y=35\ \ (1)} \atop {x+2y=50\ \ (2)}} \right. \\`

From (2) subtract (1):

`y=15\ \ \ \ \ \Rightarrow\\x+15=35\\x=20.`