Question

A man has certain note of denomination 20 and 5 which amount to 380.If the number of notes of each kind are interchanged, they amount to 60 less than before.Find the number of notes of each denomination

Answer 1

Let the man has
'X' no. of Rs 20 notes and 'Y' no. of Rs 5 notes
then according to question
20X+5Y=380 (1)
now if notes of each kind are interchanged our equation becomes
20Y+5X=380-60
20Y-5Y=320 (2)
now by solving equation 1 &2 we get
Y=12 & X=16