Question 1100327
I answered this very question a few days ago Question 1100013 
It was posted in algebra in finance
20% off means he paid 80%
25% off means he paid 75%
10% off means he paid 90%
2340*.80*.75*.90=1263.60

1263.60/2340=0.54
54% of original price  is a discount of 46%
.80*.75*.90=.54
.46*2340=1076.40
check
2340-1076.40=1263.60
ok