Bunuel
Phone plan A charges $1.25 for the first minute and $0.15 for every minute thereafter. Phone plan B charges a $0.90 connection fee and $0.20 per minute. Which of the following equations could be used to find the length, in minutes, of a phone call that costs the same under either plan?
(A) 1.25 + 0.15x = 0.90x + 0.20
(B) 1.25 + 0.15x = 0.90 + 0.20x
(C) 1.25 + 0.15(x – 1) = 0.90 + 0.20x
(D) 1.25 + 0.15(x – 1) = 0.90 + 0.20(x – 1)
(E) 1.25 + 0.15x + 0.90x + 0.20 = x
Let 'x' be the number of minutes.
Phone plan Acharges $1.25 for the first minute and $0.15 for every minute thereafter.
So charges=1.25*1+0.15(x-1)
Phone plan Bcharges a $0.90 connection fee and $0.20 per minute.
So charges=0.90*1+0.20x
Given, charges for x number of minutes is the same under both the plans.
So, 1.25*1+0.15(x-1)=0.90*1+0.20x
Or, 1.25 + 0.15(x – 1) = 0.90 + 0.20x
Ans. (C)