Derek can read x pages in 5 minutes. At this rate, how long will it

Question

Derek can read x pages in 5 minutes. At this rate, how long will it take him to read p pages?

A. 5p/x 
B. 5x/p 
C. p/(5x) 
D. 5/(px) 
E. px/5

suresh8055 · Answer

As given
x pages in 5 min, so pages per min = x/5
for P pages time = No .of pages /Pages per min
=p/x/5
=5p/x

Hence A

GMATinsight · Answer

x page in 5 mins

i.e. 1 page in 5/x mins

i.e. p pages in (5/x)*p

Answer: option A

ScottTargetTestPrep · Answer

The rate for Derek is x/5, is it takes Derek p/(x/5) = 5p/x minutes.

Answer: A

generis · Answer

Another approach: assign values. Pick values that prevent your having to work with fractions less than 1 (e.g. don't pick x = 1 and p = 2)

Let x = 10 pages
Let p = 20 pages

Derek reads   \frac{10pgs}{5mins}  . How long to read 20 pages?

Mental math: 
Twice as many pages, twice as much time = 10 minutes, OR

\frac{10pgs}{5mins}=\frac{20pgs}{X mins} 
 10 * X = 5 * 20 
 10X = 100  
 X = 10   minutes

Use x = 10, p = 20. Find the answer that yields 10.

Eliminate D and E immediately. Look at numerators and denominators. D is too small and E is too large.

A. 5p/x
  \frac{(5*20)}{10}= \frac{100}{10} = 10   MATCH

B. 5x/p
  \frac{(5*10)}{20}= \frac{50}{20}=\frac{5}{2}   NOT A MATCH

C. p/(5x)
  \frac{20}{5*10}= \frac{20}{50}   NOT A MATCH

D. 5/(px) - dismiss. It's tiny.

E. px/5 - dismiss. It's huge.

ANSWER A

* With this method, you must check all answers that you cannot eliminate immediately, such as D and E here. If more than one answer yields 10 (rare), pick a new set of numbers.

bumpbot · Answer

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Derek can read x pages in 5 minutes. At this rate, how long will it

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Derek can read x pages in 5 minutes. At this rate, how long will it

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