If snow accumulation increased at a constant rate of 30 millimeters pe

Question

If snow accumulation increased at a constant rate of 30 millimeters per hour during a certain snowstorm, how many seconds did it take for snow accumulation to increase by 1 millimeter?

A. 1/120
B. 1/60
C. 1/20
D. 20
E. 120

BrentGMATPrepNow · Accepted Answer

Let's keep listing EQUIVALENT RATES until we get to  1  millimeter

30  millimeters per  hour  =  30  millimeters per  60 minutes 
=  30  millimeters per  3600 SECONDS 
=  3  millimeters per  360 SECONDS 
=  1  millimeter per  120 SECONDS

Answer: E

Cheers,
Brent

generis · Answer

I suspect the trap answer is A. It is easy to overlook units.

Shortcut: 1 hour = 3600 seconds
  \frac{30mm}{1hour}=\frac{30mm}{3600secs}=\frac{1mm}{120secs}

Units are not the same. The answer is not A. In 120 seconds, 1mm of snow will accumulate.

Answer E

No shortcut:   (\frac{30mm}{1hour}*\frac{1hour}{60mins}*\frac{1min}{60secs})=\frac{30mm}{(60*60)secs}=\frac{30mm}{3600secs}

In the parentheses, hours and minutes cancel. Factor out 30, write the final units:   \frac{1mm}{120secs}

Answer E

ScottTargetTestPrep · Answer

Recalling that 1 hour = 3600 seconds, we can create the equation:

30/3600 = 1/x

1/120 = 1/x

x = 120

Answer: E

Hero8888 · Answer

I haven't seen on GMATCLUB the method that I use (that I was taught in my school to convert ratios). I hope it will be helpful, at least it makes my life easier. See attachment below

Kinshook · Answer

Given: Snow accumulation increased at a constant rate of 30 millimeters per hour during a certain snowstorm.

Asked: How many seconds did it take for snow accumulation to increase by 1 millimeter?

30 millimeters snow is accumulated in 1 hours = 3600 seconds
1 millimetre snow will be accumulated in = 3600/30 = 120 seconds

IMO E

Basshead · Answer

30 millimeters = 1 hour
 \frac{1}{2}  millimeters = 1 minute
 \frac{1}{120}  millimeters = 1 second

\frac{1}{120} * 120 seconds = 1 millimeter

Answer is E.

spy2206 · Answer

Bunuel  what does tag gmat prep focus mean-- are they from focus edition official guides or are they from mock

Bunuel · Answer

Those are from mocks.

AnishPassi · Answer

While reading the question, I notice that there’s some variation in units going on. The key in this question is to keep track of the units.

The given constant rate is 30 millimeters per hour.

We are asked to figure out the time it would take for 1 mm of snow to accumulate  in seconds .

Let me get into minutes first.

30 mm in 60 minutes. 
 So, 1 mm in 2 minutes.

Answer choices A, B and C are less than 1 second. Too small. Rejected.

Even 20 seconds (D) is too low.

2 minutes =120 seconds. (E).

If snow accumulation increased at a constant rate of 30 millimeters pe

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 Problem Solving (PS) Questions

If snow accumulation increased at a constant rate of 30 millimeters pe

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