100 ÷ 10 = 10
There are 47 ways.
6458546
245
420 10p coins
I make it 4,562.
73
ten 10 x 10p = 100p = £1
245 of them.
There are 47 ways.
6458546
The one that is not a 10p is a 20p. The other coin is a 10p. The question/riddle does not say that neither coin is a 10p, only that one of them is not.
17p = 2p + 5p + 10p
245
420 10p coins
I make it 4,562.
150 10p coins.
20p and 10p