Answer:
Provider A 225
Provider B 100
A would be the best option as provides with better surplus
Explanation:
P to make Qd = 0
150/50 = 3
Provider A
the surplus will be
Qd = 150 - 50P
IF there is a flat fee then, variable P will be 0 thus, our friend will do
Qd = 150 minutes
The surplus will be:
(3 - 0) x 150/2 = 225
Provider B
Qd = 150 - 50(1)
Qd = 150 - 50 = 100
It will make call for 100 minutes.
The surplus is:
(3 - 1) x 100/2 = 100