Answer:
A would be the best plan for the given use of 120 minutes durng daytiem and 40 minutes evening call.
B)
for only daytieme calls as Plan A has a lower rate in dayime than B it wil lbe always preferable over it. Now as point C has a flat rate plant A will be a better option below it:
$80 / 0.45 = 178 minutes
After this point plant A will surpass the 80 dollars flat rate charged by C therefore, be more expensive
from 0 to 178 Plan A
from 178 and above Plan C
Explanation:
Plan A Plan B Plan C*
daytime 0.45 0.55 0.40
evening 0.20 0.12 0.40
*Plan C cost per minute start after 200 minutes.
at 120 daytime and 40 evening call:
A) 120 x 0.45 + 40 x 0.20 = 62.00
B) 120 x 0.55 + 40 x 0.12 = 70.80
C) $200