Bunuel

The table above shows all applicable charges for 2 phone lines, Line 1 and Line 2, under 2 plans, Plan A and Plan B. Both plans require a monthly fee per phone line and Plan B requires an additional onetime Line Activation Fee. If n is the number of months for which the total charges for 2 lines under Plan A are equal to the total charges for 2 lines under Plan B, what is n ?
A. 4
B. 5
C. 8
D. 10
E. 16
Source: Skills InsightAttachment:
2022-05-08_13-18-26.png
For n months total plan A cost for both the lines:
\( 0+n( 40+15 ) ... \) installation charges are 0 and monthly rent are 40 and 15 respectively.
For n months total plan B cost for both the lines:
\(50+30 + n(35+10 )...\) Note: Installation charges are \(50 \) and \(30 \) respectively and are charged only once well as rent, monthly.
Also given total cost for n months for both the lines are equal for both the plans:
Hence :Both lines, total plan A cost for n months = Both lines, total plan B cost for n months
-> \(0+n( 40+15 ) = 50+30 + n(35+10 )\)
->\(55n =80+45n\)
->\(10n=80\)
->\(n=8\)
Ans C