There are five 20p in £1.
Therefore, 15 x 5 = 75 twenty pence pieces.
40 ways.
9
21 ways
20 + 8 = 28p
Different countries have different coinage. You have not specified a country. In the UK, for example, you could do 50p + 20p + 20p + 20p + 10p + 5p = 1.25p
41
40 ways.
7
41
9
How many 20ps do I need to make up£2
The answer is 100/(20p) = 5/p
20p
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There are 10 ways.
21 ways
20 + 8 = 28p