I believe the answer is 55.
$21 for the first. $20 for the second and $7 for the third
450/25= 18
where 450 is $4.50 and 25 is one quarter. there will be 18 quarters.
560-450=110
110/10=11
where 110 is $1.10 and 10 is one dime. there will be 11 dimes.
11+18= 29
where 11 is total number of dimes and 18 is total number of quarters. and 29 is total number of coins
I 100% agree with this statement