Question

a man has certain notes of denomination of rupees 20 and rupees 5 which amount to rupees 380 if the number of notes of each kind is interchanged the amount to rupees 60 less as before. Frame an equation according to the given question

Answer 1

Let , the number of 20 rupees note be x .
And , the number of 5 rupees note be y.
According to the question ,
20x + 5y = 380 .

Now ,
Notes are interchanged ,
So , 5x + 20y =320 .