Given that, Asif has 36 one rupee coins.
Let the number of 5 rupee coins be x.
Number of 1 rupee coins = 4x
So,
Amount of 5 rupee coins = 5x
Amount of 1 rupee coin = 4x
Total amount = Rs.81
Hence accordpng to question,
5x + 4x = 81
9x = 81
x = 9
Hence, number of 5 rupee coins = 9
Number of 1 rupee coins = 36