Problem Solving

Hi alanforde800Maximus,

You might find it helpful to draw a picture of the activity that's described in this prompt. Based on the time for each toll (3 seconds) and the silence between tolls (2 seconds), the total length of time at 2pm would be:

(toll)(silence)(toll)
(3s)(2s)(3s)
8 total seconds

Seeing this pattern (re: the number of 'silences' is one less than the number of 'tolls), you can quickly deduce how long the total activity would be at 9am:

9 tolls + 8 silences
(9)(3) + (8)(2)
27 + 16
43 total seconds

Final Answer: D

GMAT assassins aren't born, they're made,
Rich

vinni.k wrote: Stem says beginning and end of the toll. It could also mean excluding the first toll and the last toll, and counting in between.

I think stem must mention that beginning and end must be included. I have seen some questions in which word "including" or similar word is mentioned.

I don't think that interpretation is correct.

"How many seconds elapse between the beginning of the first toll and the end of the last toll?"

If a 3-second toll sounds like "bonnnnnnnnnnng" then the time would start at "b" of the first toll and end at "g" of the last (ninth) toll.

Cheers,
Brent

alanforde800Maximus wrote:A certain cathedral bell marks every hour by ringing a number of times equal to the current hour ( for example, at 2:00PM, the bell rings twice). Each toll of the bell lasts for three seconds, with 2 seconds of silence between tolls. At 9:00AM, how many seconds elapse between the beginning of the first toll and the end of the last toll?

a) 52
b) 48
c) 45
d) 43
e) 40

Rich's solution is solid, so I won't rehash that.
Another option is to write out the entire event.
Let T represent each second the bell Tolls
Let S represent each second of Silence

So, the 9 tolls (from start to end) look like this:
TTTSSTTTSSTTTSSTTTSSTTTSSTTTSSTTTSSTTTSSTTT

There are 43 letters, so the time is 43 seconds.

Answer: D

Hi vinni.k,

If you were to interpret the prompt in the way that you described, then you would start with the beginning of the first 'silence' and end with the end of the last 'silence', which would make the total....

8 silences + 7 tolls = 8(2) + 7(3) = 37 seconds

This answer is NOT among the five answer choices, so this CANNOT be the solution. One of the great things about PS questions is that if "your answer" isn't there then that means you've made some kind of mistake (that you might be able to go back and fix).

GMAT assassins aren't born, they're made,
Rich