C:t=2:3
t:h=2:1
multiply first equation by 2 and 2nd by 3
c:t=4:6
t:h=6:3
so
c:t:h=4:6:3
if t is 4 more than c
t is 6 units and c is 4
6-4=2
so 4=2 units
2=1 unit
hollly is 3 units
3*2=6
holly has 6 cards
The zero is in the one place, so Monica has 10 dollars while her brother owes her 15$.