Question

You are looking at 2 cell phone company plans.

Company Sharp has an initial charge of $25 per month plus 50 cents for each call

Company Penn charges of $40 per month plus 20 cents per call.

When will it be cheaper to use the plan from Company Penn?

Answer 1

$1=100 cents

$25=2500 cents

$40=4000 cents

Number of call in one month=x

Now plan of Sharp company:

Initial charge per month=$25=2500 cents.

Cost of each call=50 cents.

Cost of call per month=50X

Total cost for one month= (2500 + 50X) cents.

Plan of Penn company:

Initial charge for one month=$40= 4000 cents.

Cost of each call=20 cents.

Cost of call per month=20X

Total cost for one month=(4000+20X) cents.

It is asked in the question that when the plan of company Penn will cheaper.

Therefore

(4000+20X) < (2500+50X)

(4000 - 2500) < (50X - 20X)

1500 < 30X

(1500/30) < X

50 < X

X > 50

Hence if number of call per month is more than 50 then the plan of company Penn will be cheaper