Algebraic Problem

[Abdulla]

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, with no monthly fee, what is the maximum the customer on the calling plan could have saved over 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

OA is C

[yogami]

dang!! I couldn't do this one. Anybody ??? I tried 1.6*3 + 0.8*57 = 50.4 as the regular price without discount and without any monthly fee.
Then if you consider monthly fee and discount for the 1 hour call it will be
25 + 50.4*0.4 and then subtracting the two gave me 4. or 5. something savings. I might have misinterpreted this one for sure

[AymanMath]

can any body explain !!!

[tohellandback]

here we go!!
" maximum the customer on the calling plan could have saved "
so for this we need to charge the customer maximum so that the discount 40% is maximum.
this is possible when the customer made twenty 3 minute calls and no other calls
total call cost for him=60*1.6=96
40 percent=.4*96=38.4
he already paid 25 dollars. so savings are 38.4-25=13.4

[rah_pandey]

Please check here.

https://www.beatthegmat.com/kaplan-t39076.html#167411