A call to Rosie’s Psychic Hotline

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A call to Rosie's Psychic Hotline costs $5.99 for the first 2 minutes and $1.99 for each additional minute. Stuart called the hotline for x minutes, where x is an integer. How many minutes long was the call?

(1) The total charge for the call was $11.96.
(2) The charge for the last 3 minutes of the call was $0.01 less than half the total cost of the call

Which of the statement is sufficient?

OA D
Source: — Data Sufficiency |

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by Jay@ManhattanReview » Tue Dec 19, 2017 12:48 am
lheiannie07 wrote:A call to Rosie's Psychic Hotline costs $5.99 for the first 2 minutes and $1.99 for each additional minute. Stuart called the hotline for x minutes, where x is an integer. How many minutes long was the call?

(1) The total charge for the call was $11.96.
(2) The charge for the last 3 minutes of the call was $0.01 less than half the total cost of the call

Which of the statement is sufficient?

OA D
Total charge = 5.99 + 1.99(x - 2)

(1) The total charge for the call was $11.96.

5.99 + 1.99(x - 2) = 11.96

We can get the the unique value of x. There is no need to calculate it as this is a DS quetion. If we are sure that we would get a unique value, we need not compute it. Sufficient.

(2) The charge for the last 3 minutes of the call was $0.01 less than half the total cost of the call.

Charges for the last 3 minutes = 3*1.99 = 5.97 ---(1)
The total charge = 5.99 + 1.99(x - 2) => Half the total cost = 1/2[5.99 + 1.99(x - 2)] ---(2)

(1) = (2) - 0.01

5.97 = 1/2[5.99 + 1.99(x - 2)] - 0.01

We can get the the unique value of x. Sufficient.

The correct answer: D

Hope this helps!

-Jay
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