RTW Problem CAT Exam

[clarence.booth]

I'm curious as to how I could have solve this problem using a RTW chart if the arithmetic wasn't immediately recognizable to me. Here's the problems and the answer:

Working at a constant rate, a chocolate factory produces 144,000 chocolate truffles per day. If the factory operates 16 hours a day, how many truffles are produced every 5 minutes?


250

500

750

1000

1250

The factory produces 1/16 of the truffles each hour; since we want to know how many truffles are produced in 5 minutes, and there are 60 minutes in an hour, we simply have to multiply the total number of truffles produced per day by 1/16 and 1/60 and 5:

144,000 × 1/16 × 1/60 x 5 = 144,000 x 1/16 x 1/12 = 144,000 x 1/192 = 750

The correct answer is C.

[tim]

The RTW chart is just a way to organize the arithmetic, which should help you if you weren't sure how to do the arithmetic straight away. Show us what you have so far in your RTW chart and we can help you from there.

Ultimately though, this is less of a rates problem and more of a ratios problem, so you want to learn how to recognize that and implement the arithmetic so you can save yourself a lot of time.

[clarence.booth]

Tim,

Thanks for the reply. Given your re: that this is a ratio problem, can you tell me how I would have distinguished this as such and in which chapter of the course work can I review the approach? Admittedly, I saw the word 'rate' and assumed RTW.

Thanks, Tim.

[tim]

Mainly because you're dealing with two different hypotheticals of the same context - i.e. "what if it's 5 minutes rather than 16 hours". Most rates problems involve, for instance, two different machines operating under fixed time constraints. Ultimately though, you should still be able to solve this one using the standard RTW framework if you don't catch the ratios shortcut.

[RonPurewal]

Tim,

Thanks for the reply. Given your re: that this is a ratio problem, can you tell me how I would have distinguished this as such and in which chapter of the course work can I review the approach? Admittedly, I saw the word 'rate' and assumed RTW.

Thanks, Tim.

You can do it as a rate problem.
Production rate = 144,000 items / (16*60) minutes. That will give you a number of items produced per minute.
Multiply that by 5 minutes.