What is the maximum the customer could have saved...

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A customer using a certain telephone calling plan pays a fee of $25 per month, and then receives a discount of 40% on the regular charge for all calls made to country A. If calls to country A are regularly charged at $1.60 per minute for the first 3 minutes, and $0.80 per minute for each minute thereafter, what is the maximum the customer could have saved over the regular prices if he was charged for 1 hour of calls made to country A in a certain month?

A. $8.75
B. $12.00
C. $13.40
D. $17.40
E. $24.40

The answer is C. $13.40
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by tohellandback » Sun Aug 16, 2009 6:11 pm
since we need to maximiz the amount saved
that is, we need to maximize the amount (40% on the regular call charges)
for this we need to maximize the call charges
best way is make only under 3-minutes calls
1.6 per minutes.
for one hour: total is 1.6 *60= 96 dollars

40% of 96= 38.4 dollars
he paid 25 dollars already so savings=38.4-25
=13.4 dollars
Answer C

(I would also point one thing here, if the total time were let's say only 30 minutes, the max savings would be 25 dollars)
The powers of two are bloody impolite!!