Is the number of seconds required to travel d1 feet at r1

Question

Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?

(1) d1 is 30 greater than d2.

(2) r1 is 30 greater than r2.

OPEN DISCUSSION OF THIS QUESTION IS HERE: is-the-number-of-seconds-required-to-travel-d1-feet-at-r1-143694.html

Show Answer

Official Answer

E

Solving this question helps. Taking a timed set of similar questions in GMAT Club Forum Quiz → is even better.

BenchPrepGURU · Answer

That's not much of an explanation. Since neither piece of data combines information about rate and distance, we can see that this will be a C or an E. I would simply try some extreme cases.
d1 = 60 and d2 = 30 with r1 = 31 and r2 = 1
It will take approximately 2 secs to travel 60 feet at 31 ft/sec and 30 secs to travel 30 feet at 1 foot per sec.
Now try
d1 = 60 and d2 = 30 with r1 = 120 and r2 = 90
It will take 0.5 seconds to travel 60 ft at 120 ft/sec and 0.33 secs to travel 30 ft at 90 ft/sec.

So E.

BenchPrepGURU

harshavmrg · Answer

Individually the points 1 and 2 does not help

d1, r1 are given and d2, r2 are given

so t1=d1\r1 and t2=d2\r2

question is is t1>t2?

1. gives d1=30+d2...does not help
2. gives r1=30+r2...does not help

together
d1=d2+30
r1=r2+30

for ex d2=2 r2=3
so d1=32 and r2=33
so t1=32/33 and t2=2/3
t1>t2

also for ex d2:20 and r2=30
so d1=50 and r2=60

so t1=50/60 = 0.833 and t2=2/3=0.667
t1>t2

also for ex d2=30 and r2=20
d1=60 and r2=50
so t1=6\5 = 1.2 and t2=3/2=1.5
t1<t2

so from ex 1 and 2 it says YES and 3rd example says no..

hence E

dabral · Answer

One can also approach it algebraically. Here is a video explanation. https://www.gmatquantum.com/list-of-vide ... -ds87.html

144144 · Answer

I guess it might be tricky because u need to remember that d1/r1 could be bigger or smaller than 1. understanding this - solving the question in no time.

Bunuel · Answer

Is the number of seconds required to travel d1 feet at r1 feet per second greater than the number of seconds required to travel d2 feet at r2 feet per second?

We need to find whether \(\frac{d_1}{r_1}>\frac{d_2}{r_2}\).

(1) d1 is 30 greater than d2 --> \(d_1=d_2+30\). Nothing about the rates. Not sufficient.
(2) r1 is 30 greater than r2 --> \(r_1=r_2+30\). Nothing about the distances. Not sufficient.

(1)+(2) The question becomes whether \(\frac{d_2+30}{r_2+30}>\frac{d_2}{r_2}\). Now, if \(d_2=r_2\), then \(\frac{d_2+30}{r_2+30}=\frac{d_2}{r_2}\), thus in this case the answer would be NO but if \(d_2=1\) and \(r_2=2\), then in this case \(\frac{d_2+30}{r_2+30}=\frac{31}{32}>\frac{1}{2}=\frac{d_2}{r_2}\), thus in this case the answer would be YES. Not sufficient.

Answer: E.

OPEN DISCUSSION OF THIS QUESTION IS HERE: is-the-number-of-seconds-required-to-travel-d1-feet-at-r1-143694.html

Is the number of seconds required to travel d1 feet at r1

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

GMAT Data Sufficiency (DS) Questions

Is the number of seconds required to travel d1 feet at r1

Prep Toolkit

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