2023 2024 Student Forum > Management Forum > Main Forum

 
  #2  
25th March 2016, 01:51 PM
Super Moderator
 
Join Date: May 2012
Re: Work Rate Problems GMAT

The approach is to put simple work rates into percentages (rather than fractions).

The common sense approach is basically this: break everything down into a unit of time that is easy to work with, and just figure out what happens during that time. Could be an hour, ten minutes, etc., depending on the question. Then add them up. With combined work rate, we’re really adding the efforts, never multiplying them.

1) Running at the same rate, 8 identical machines can produce 560 paperclips a minute. At this rate, how many paperclips could 20 machines produce in 6 minutes?
(A) 1344
(B) 3360
(C) 8400
(D) 50400
(E) 67200
2) Jane can make a handcrafted drum in 4 weeks. Zane can make a similar handcrafted drum in 6 weeks. If they both work together, how many weeks will it take for them to produce 15 handcrafted drums?
(A) 30
(B) 36
(C) 70
(D) 80
(E) 150
3) Machines P and Q are two different machines that cover jars in a factory. When Machine P works alone, it covers 1500 jars in m hours. When Machines P and Q work simultaneously at their respective rates, they cover 1500 jars in n hours. In terms of m and n, how many hours does it take Machine Q, working alone at its constant rate, to cover 1500 jars?
(A) m/(m + n)
(B) n/(m + n)
(C) mn/(m + n)
(D) mn/(m – n)
(E) mn/(n – m)

Huge Idea #1: The "Craftsmanship" Equation

You might be acquainted with the separation mathematical statement, D = RT ("separation rises to rate times time"), at times recognized as the "earth" comparison. For reasons unknown, comparison is only a particular occasion of an a great deal more broad mathematical statement. In that mathematical statement, R, the rate, is separation per time, however in non-separation issues, rate can be anything after some time — torques created every hour, houses painted every day, books composed every decade, and so on. In these cases, ordinary of work issues, we are no more worried with "separation" per time, however with the measure of something delivered per time. We utilize A to speak to this sum (the quantity of wrenches, the quantity of houses, and so on.), and the mathematical statement turns into A = RT. Now and again people recollect this as the "craftsmanship" comparison.

Huge Idea #2: Rates are Ratios

"Rate" and "proportion" have the same Latin root: truth be told, they additionally impart a Latin root to the "judiciousness" of our psyches, however that is a dialog that would raise to our noses into Pythagorean and Platonic theories. The fact of the matter is: a rate is a proportion, that is to say, a portion. In fact, any portion, any proportion, in which the numerator and the denominator have distinctive units is a rate. Fuel effectiveness (mpg) and cost per unit and most baseball parts (ERA, BA, OBP, SLG, and so forth.) are rates. Cash rates and trades rates are normal budgetary business sector rates that, humorously, never show up on the GMAT — - go figure! Most GMAT rates have time in the denominator, and it's a rate of how quick function is being done or how quick something is being delivered or fulfilled.

Enormous Idea #3: Add Rates

Most by far of work issues on the GMAT include two individuals or two machines and correlations of their individual creation to their joined generation. Questions #2 and #3 above are of this structure. The inquiries will regularly give you data about times and about sums, and what you have to know is: you can't add or subtract times to finish an occupation and you can't include or subtract measures of work; rather, you include and subtract rates.


Quick Reply
Your Username: Click here to log in

Message:
Options

Thread Tools Search this Thread



All times are GMT +5. The time now is 09:55 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
SEO by vBSEO 3.6.0 PL2

1 2 3 4