#### Answer

$12$

#### Work Step by Step

We have 3 coins that are worth less than 0.25: 0.01, 0.05 and 0.10. Therefore the possibilities:
$2×0.10+0.05$
$2×0.10+5×0.01$
$0.10+3×0.05$
$0.10+2×0.05+5×0.01$
$0.10+1×0.05+10×0.01$
$0.10+15×0.01$
$5×0.05$
$4×0.05+5×0.01$
$3×0.05+10×0.01$
$2×0.05+15×0.01$
$1×0.05+20×0.01$
$25×0.01$
Therefore there are 12 possibilities.