Algebra help?

Question

I know this is probably a really easy problem, but I've been doing summer review problems all day, I skipped this one and came back to it so now my brain is fried so please help, heres the problem:

At Indianapolis Speedway, one lap is 2.5 miles in length. The average speed of an Indy racing car is 190mph.

How many seconds would it take to complete one lap?

I thought it would be

190mph/1mile = 11400sec/1mile = 20500sec/1lap or 2.5 miles

is that right?

Answer 1

First, ask yourself: "Would it take a race car 20,500 seconds to make it around 2.5 miles?" Seems EXTREMELY slow, don't you think? So let's go back to the drawing board. It's always best to set up your problem with what you know and what you're trying to find out:

Given:
distance = 2.5 miles
velocity = 190 miles/1 hour

Find: time (in seconds)

Now that you know what you have, determine the equation that you'll need to solve this problem. This is a problem related to the velocity formula, but you want to solve for time:

Velocity = Distance/Time
v = d/t
t = d/v (by multiplying both sides by "t" and dividing by "v")

Before you plug in all of your information, make sure you have the same units. "Mile" is consistant for distance, but time changes between "hour" and "seconds". The conversion factor for these two is determined by their relationship:

1 hour = 60 min
1 min = 60 sec
1 hour = 60 min x 60 sec
1 hour = 3600 sec

Therefore, the racecar is travelling at 190 miles per 3600 sec, or 190mi/3600sec.

Now plug in all that you were given into your reformed velocity equation:

t = d/v
t = 2.5mi/(190mi/3600sec)
t = 47.368 sec
t = 47 sec (rounded)

I did the math for you to show you the difference between 47 seconds and 20,500 seconds. One sounds a little bit more like a racecar, huh? This kind of problem gets a lot easier the more you play with it. I hope my explanation helped!

Answer 2

No. no . no! Your equations don't make any sense, plus it's asking about time. Look:
time = distance / speed
if one lap = 2.5 miles and the car is moving at 190mph, the time taken to cover this distance (one lap) t is given by:
t = 2.5 / 190 = 0.013157894 hours.
In seconds this will be 0.013157894 multiplied by 3600 (I hour = 60 minutes, 1 minute = 60 seconds (60 by 60 =3600).
Therefore, t = 47.36842105 or 47.37 to 2 decimal places.

Answer 3

If you go 190 miles/hr that means you are going 3.1666 miles/minute and .0527 miles/second. [190/3600 sec/hr]

Since it takes 1 second to go .0527 miles you divide .0527 into 2.5 to figure out how many seconds it will take to go 2.5 miles. That comes to your answer of 47.4383 seconds.

Your answer doesn't make sense b/c if it takes 1 hour to go 190 miles and the track is only 2.5 miles it would take a LOT LESS than 1 hour to go 1 lap.
Since an hour is 3,600 seconds, the answer of 20,500 sec is WAY too High.

Answer 4

first, the 190 mph = 190 miles Per Hour....not per mile :)

i think u have to do a ratio where two equations equal eachother to find the missing "x":


190 miles/ 1 hour = 2.5 miles / x

cross multiply:

190x = 2.5

x = 2.5/190

x = 0.01315

so it takes 0.01315 of an hour to finish 1 lap. to translate that into seconds, u have to multiply by 60 min, and 60 seconds

that calculates to 47.34 seconds

i hope that makes sense..good luck!

Answer 5

t = d/r
t = 2.5/190 (in hours)
convert to seconds:
t = 3600(2.5/190)
t = 900/19 seconds, approx 47.39 seconds

Answer 6

It's been awhile, but I'll bite.
Let's try this:
1 hour = 3600 seconds, so 190/3600:2.5/x
3600/190 = 18.947 (one mile)
18.947 X 2.5 (one lap) = 47.368....

Answer 7

190 miles per hour / 3600 seconds /hr =

speed = 0.05278 miles/second.

speed = distance / time
time = distance/speed
time = 2.5 miles / 0.05278 miles/second
time = 47.37 seconds.

Answer 8

For increasing cubic binomials the final formula is as follows: (a + b) ^ 3 = a^3 + 3*a^2*b^a million + 3*a^a million*b^2 + b^3 on your case, a is x and b is -y^5 So (x - y^5)^3 = x^3 + 3*x^2*(-y^5)^a million + 3*x^a million*(-y^5)^2 + (-y^5)^3 Simplified: =x^3 - 3x^2*y^5 + 3x*y^10 - y^15 :D

Answer 9

2.5/190=answer. Then answer*60=new answer. Then new answer*60=answer to problem. * means times (multiplication).

Answer 10

Average Speed = [Distance Traveled]/[Time Taken to Travel that Distance]
so, time =distance/avg speed = 2.5miles/190m.p.h=0.01316 hrs.
your ans is in hrs. to convert to secs multiply by 3600. since
1hr= 3600sec

0.01316 * 3600= 47.4sec is your Ans