Question

a sum of rs 800 is in the form of denominations of Rs 10 and rs 20 if the total number of notes is 50 find the number notes of each type

Answer 1

let the number of RS 10 notes=x
let the number of RS 20 notes=y
x+y=50
10x+20y=800

x+y=50 * 10
simultaneous equations

10x+10y=500
10x+20y=800

-10y=-300
10y=300
y=30

x+30=50
x=20

number of RS 10 notes=20
number of RS 20 notes=30