A telephone company charges x cents for the first minute of a call and

Question

A telephone company charges x cents for the first
minute of a call and charges for any additional time
at the rate of y cents per minute. If a certain call
costs $5.55 and lasts more than 1 minute, which of
the following expressions represents the length of
that call, in minutes?
(A) $555 - x / y$
(B) $555+x- y/y$
(C) $555-x+ y/y$
(D) $555-x- y/y$
(E) $555/x+ y$

(A)  \frac{555 - x}{y}

(B)  \frac{555+x- y}{y}

(C)  \frac{555-x+ y}{y}

(D)  \frac{555-x- y}{y}

(E)  \frac{555}{x+ y}

KarishmaB · Answer

Let us say the call lasts for n minutes.
Cost of first minute = x
Cost of next (n - 1) minutes = y(n - 1)
Then, x + y(n - 1) = 555
n = (555-x)/y + 1 = (555 - x + y)/y
Answer (C).

varunmaheshwari · Answer

Thanks Karishma..
Even i was caught in the trap of answer A.

KarishmaB · Answer

I am always cautious while marking (A) as my answer. Not because the probability of it being the answer is low, but because if the question has a trap people could fall for, then the question maker will set (A) as that particular lucrative option. (Hell, I do that when I make questions! Kind of a bait!) So I like to double check especially if it seems too easy.

The logic of (555 - x)/y was perfectly valid. The only missing point was that these are the (n -1) additional minutes. You did not account for the 1st minute. So total time will be (555 - x)/y + 1 which is the same as option (C): (555 - x + y)/y

And yes, parentheses will definitely be there in the exam in such a question. 555 - x + y/y = 555 - x + 1 (Since it didn't make any sense here, it was obvious that there are parentheses in the options). Rest assured, there will not be any ambiguity in the actual exam.

ScottTargetTestPrep · Answer

Since x and y are in cents, we should start by expressing $5.55 in cents, which is 555 cents. We can then create the following equation where t = the length of the call, in minutes:

555 = x + y(t - 1)

555 - x = yt - y

555 - x + y = yt

(555 - x + y)/y = t

Answer: C

BrushMyQuant · Answer

Given that A telephone company charges x cents for the first minute of a call and charges for any additional time at the rate of y cents per minute. And If a certain call costs $5.55 and lasts more than 1 minute, then what is the value of length of the call

Let call duration be (1 + t) mins

=> Charge will be $X (for first min) + $y * t (for t additional mins)
= $X + $yt = $555 (given)
=> t =  \frac{555 - X}{y}

=> Total call duration = 1 +  \frac{555 - X}{y}  =  \frac{555-x+ y}{y}

So,  Answer will be C 
Hope it helps!

DUMDUM21 · Answer

It's pretty straight forward.
n = (555-x)/y + 1 = (555 - x + y)/y

A telephone company charges x cents for the first minute of a call and

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