Question

A sum of rs 800 is in the form of denomination of rs 10 and 20. if the total number of notes is 50 find the number of notes of each type

Answer 1

let the no. of notes of rs.20 = x
now the no of notes of rs. 10 = 50-x.
so 20x + (50-x)10 = 800
then 20x + 500 -10x = 800
now 10x = 300
so. x = 30.
there will be 30 notes of rs.20
and 20 notes of rs.10

Answer 2

ĺet the number of Rs 10 notes be x.
then the number of Rs 20 notes be 50-x.

ATQ
10x +20(50-x) =800.
10x+1000-20x=800.
-10x=800-1000.
-10x=-200.
-x=-200/10
-x=-20
x=20.

so,number of Rs 10 notes =20.
and number of Rs 20 notes =50-20=30