We are given that the charge for a telephone call between City R and City S is $0.42 for each of the first 3 minutes and $0.18 for each additional minute. We are also given that a call between the two cities lasted for x minutes. We can create the following equation:
3(0.42) + 0.18(x - 3) = total cost of the call
1.26 + 0.18x - 0.54 = total cost of the call
0.18x + 0.72 = total cost of the call
We must determine the value of x.
Statement One Alone
The charge for the first 3 minutes of the call was $0.36 less than the charge for the remainder of the call.
Using the information in statement one, and from the given information, we can create the following equation:
1.26 = (0.18x - 0.54) - 0.36
0.78 = 0.18x - 0.54
2.16 = 0.18x
x = 12
Statement one alone is sufficient to answer the question. We can eliminate answer choices B, C, and E.
Statement Two Alone
The total charge for the call was 2.88.
Using the information in statement two, and from the given information, we can create the following equation:
0.18x + 0.72 = $2.88
0.18x = $2.16
x = 12
Answer: D