If an object travels 100 feet in 2 seconds, what is the

Question

If an object travels 100 feet in 2 seconds, what is the object’s approximate speed in miles per hour? (Note: 1 mile = 5280 feet)

A. 3.4
B. 3.8
C. 34
D. 38
E. 340

KarishmaB · Accepted Answer

Conversion questions are best dealt using a one step approach. 
Let me illustrate: Let's say we want to convert a speed of 100 miles/hour to feet/sec.

Speed = 100 miles/1 hour = (100 x 5280 feet)/(1 x 3600 sec)= 146.67 feet/sec

So, simply convert the units to what you want along with the conversion factor.

Let's take your question now.
If an object travels 100 feet in 2 seconds, what is the object’s approximate speed in miles per hour? (Note: 1 mile = 5280 feet)

Speed = 100 feet/2 sec = (100×1/5280 miles)/(2×1/3600 hour) = 5x3600 miles/528 hr = 34 miles/hr

Note: Since 1 mile = 5280 feet, hence here to convert we say 1 foot = 1/5280 miles.

Bunuel · Answer

100  feet in 2 seconds;

100*\frac{3,600}{2}=50*3,600  feet in 1 hour;

\frac{50*3,600}{5,280}\approx{34}  miles in 1 hour.

Answer: C.

pzazz12 · Answer

thanks for your better explanation......

subhashghosh · Answer

1 mile = 5280 feet

=> 1 feet = 1/5280 miles

If the object ravels 100 feet in 2 sec

then it travels 100/2 * 60 * 60 feet in 1 hour (1 hr = 60 min * 60 sec)

= 3600 * 50 feet in 1 hour

= 180000 feet in 1 hr

= 180000/5280 miles in 1 hour

= 18000/528 miles/hr ~ 34 miles/hr

Answer - C

jamifahad · Answer

In 2 seconds ----100feet
In 1 second----50feet
In 3600 seconds(1hour=3600sec)---3600*5feet.

Now 5280 feet = 1 miles
so, 3600*5 feet= 3600*5/5280.
Now use approximation.. (36*5)/5280 * 100 = 180/5280 *100 or 18/5280 * 1000= 3/88 *1000. 
Now 3/90= 1/30= .03
So 3/88*1000 ~ .03*1000=33.3~34.

Idea is to not multiply anything until last few steps when you can use approximation better.

hussi9 · Answer

speed= 100 feet/2 sec
 = 50 feet /1 sec
 = 50*60*60 feet / hours

Now divide the entire distance traveled into number of miles

it gives 18000/5280

~35 Hence choice c

galiya · Answer

100 (feet)/2 (sec) *1 (mile)/5280 (feet)* 3600 (sec)/1 (hour) --> cancel out (feet) and (sec) and you will get

(100*3600)/(2*5280) = 34.09

BrushMyQuant · Answer

1 mile = 5280 feet => 1 feet = 1/5280 mile

1 hr = 3600s => 1s = 1/3600 hr

If an object travels 100 feet in 2 seconds => speed = 100/2 feet/s = 50 feet/s = 50 *(1/5280) / (1 *(1/3600)) miles/hr
= 3600 * 50 / (5280) miles/hr = 18000/ 528 miles/hr ~ 18000/525 = 180 * 4/ 21 miles/hr = 240/7 miles/hr ~ 34miles/hr

So, Answer is C(34)

Hope it helps!

KanupriyaS · Answer

Thanks! nice explanation! helped me understand.

Bunuel · Answer

Other conversion problems to practice: if-an-object-travels-100-feet-in-2-seconds-what-is-the-103364.html the-rear-wheels-of-a-car-crossed-a-certain-line-0-5-second-135753.html a-train-traveling-at-a-constant-speed-down-a-straight-track-87124.html a-welder-received-an-order-to-make-a-1-million-liter-126154.html a-car-traveling-at-a-certain-constant-speed-takes-2-seconds-126658.html if-an-automobile-averaged-22-5-miles-per-gallon-of-gasoline-109083.html if-1-kilometer-is-approximately-0-6-mile-which-of-the-140731.html measuring-standards-conversion-106516.html if-10-millimeters-equal-1-centimeter-how-many-square-48538.html the-speed-of-light-is-approximately-149492.html the-rear-wheels-of-a-car-crossed-a-certain-line-0-5-second-135753.html if-the-speed-of-x-meters-per-second-is-equivalent-to-the-127005.html according-to-the-formula-f-9-5-c-32-if-the-temperature-160658.html if-the-speed-of-x-meters-per-second-is-equivalent-to-the-spe-79246.html on-a-trolley-ride-around-an-amusement-park-a-child-traveler-161594.html the-distance-between-two-planets-is-3-04-10-6-light-years-161745.html Hope this helps.

smudumala · Answer

My approach is as follows:
100 feet in 2 Secs.
Therefore 50 feet in 1 Sec
50 X 60 =3000 Feet in 1 Min
And 3000 X 60 = 180000 Feet in 1 Hour

Now Conversion..... 180000/5280~=180000/5000=36
The answer should be slightly less than 36.That is C.

gmatser1 · Answer

How do you do that math fast and not screw it up? That's what I screwed up on this problem.

ENGRTOMBA2018 · Answer

You can use approximation as the given options are spread far and wide

Lets take the example of this question:

\frac{50*3,600}{5,280}

Recognize here that 36 = 18*2 and 54 = 18*3. 5280 is almost equal to 5400. Thus you can cancel out 3600 and 5280 to get 2/3 (approx.). For approximations of fractions, you need to a bit imaginative to cancel out the maximum you can.

Now the given equation reduces to 50*2/3 = 100/3 = 33.33333 which is very close to 34.

Hope this helps.

mvictor · Answer

my approach
100ft/2sec = 50ft/sec or 3000ft/min, or 180,000/hour
now..1 mile is 5280
180,000/5000 = 36
so clearly is less than 36, but smth around 30
only option C

lalania1 · Answer

difficult question. I get to the below with some work

50 *3,600/ 5,280

then I decided to approximate = 18,000/5,000 = 36.

at this point I had to decide between 34 and 38. That was the difficult part of me.

akadiyan · Answer

100 feet per 2 seconds , which translates to 3000 ft per minute.

Speed for 1 hour = (3000 * 60) / 5280 = ~ 34

Ans: C

CLIMBTHELADDER · Answer

1) First change 100ft/2seconds to 50ft/1second. 
2) Convert feet to miles = 50 * 1 / 5280 = 50/5280
3) Convert seconds to hours = 1 / (60)^2 = 
4) Divide – multiply reciprocal = (60)^2*50/5280. 
5) 3600*50=180000/5280. 
6) By looking at this fraction we conclude that it needs to be multiplied by at least 30.

Thus therefore 34. Multiplying times 8 would be make the number too large

loneo3006 · Answer

Dear Bunuel,

How would you approach this last division:  \frac{50*3,600}{5,280}\approx{34} ?

energetics · Answer

Answers are very spread out, also notice the numbers A) 3.4 and B) 3.8 are identical to C) 34 and D) 38 except for a power of 10 and E) is identical to A) and C) except with another extra power of 10.

After converting we get (50*60^2)/(5280) so quickly rounding down denominator to 5000 gives us 36 while rounding up to 6000 gives us 30 so the answer should be around the average of those, C) 34 is the only choice since D is higher than the rounded up total.

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