A certain quantity is measured on two different scales, the

Question

A certain quantity is measured on two different scales, the R-scale and the S-scale, that are related
linearly. Measurements on the R-scale of 6 and 24 correspond to measurements on the S-scale of
30 and 60, respectively. What measurement on the R-scale corresponds to a measurement of 100
on the S-scale?
A. 20
B. 36
C. 48
D. 60
E. 84

durgesh79 · Answer

look at it this way

R scale is x axis 
S scale is y axis

Points are related linerly, so points (6,30), (24,60) and (X,100) are on the same line

we need to find X

(60-30)/(24-6) = (100-60)/(X-24) 
30/18 = 40/(X-24) 
X-24=24 
X=48

klb15 · Answer

hi gmatnub, can u explain how u get 60?

FN · Answer

i get 60 as well..

60-30=(24-6)x

30=18x

x=5/3

now we know S=100, so 3/5*100=60 R

hi0parag · Answer

alternate approach:
increase of 6 to 24 in R scale corresponds to 30 to 60 in S scale
now there is a 6 point increase in r scale for every 10 point increase in S scale 
(as the scales are linear) a 40 point increase in S scale translates to a 6*4=24 point increase in R scale

Hence 60->100 in S scale means 24->48 on R scale

Ans: C

A certain quantity is measured on two different scales, the

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards