Jack's current monthly bill is
(1200 kWh +400 kWh)*($0.075/kWh) = $120
On the interval use plan, Jack's monthly bill would be
(1200 kWh)*($0.03/kWh) + (400 kWh)*($0.15/kWh) = $36 + 60 = $96
If Jack were to switch, his savings would be $120 -96 = $24.
The appropriate choice is ...
b. Jack should switch to the interval use plan, which would save him $24 per month.
I believe that this is correct. the 39 and 24 stand for how much they pay per copy but you have to add the 48 for Debbie because she had bought the copier so you needed to add that extra amount.
Unless there is no promotion like "buy 2 get 1 free" or "buy 2 get 1 for 50%" etc. then the cost of ordering multiple items is always proportional. Let's say something costs $5. Two items will cost $10, three $15, four $20 etc. These numbers are all proportional. Hopefully that's what you meant :)
Answer:
31) They divided by 100, they're suppose to times 0.86 by 100 instead, which will be 86%
33) 0.34 x 100=34%
35) we do the inverse to turn it back into
a decimal which will be 0.36

36) 16.24÷100=0.6424
