ashish has denominations of 6 and 10 rupees,how many amounts he cant pay using these denominations?

The multiples of 6 end in 2, 4, 6, 8 or 0. The multiples of 10 end in 0. So, a combination of these two always end in 2, 4, 6, 8 or 0. So, none of the numbers that end in 1, 3, 5, 7 or 9 can be written as a combination of 6 and 10. So, the answer is infinite.