Question

HELP ME PLEASE:
A car is traveling on a highway. The distance (in miles) from its destination and the time (in hours) is given by the equation d=420-65t What is the practical meaning of the d-intercept?
a.

Initially the car is 355 miles from its destination.


b.

Initially the car is 420 miles from its destination.


c.

Initially the car is 65 miles from its destination.


d.

Initially the car is 485 miles from its destination.

Answer 1

@cwrw238

Answer 2

@terenzreignz

Answer 3

PLEASE HELP ME !

Answer 4

@dumbcow

Answer 5

The d-intercept (which is really just what you are used to calling the y-intercept, here we are just using a different variable) occurs where t=0 (what you are used to seeing as x).

Answer 6

So if t=0, what does that mean IN THE CONTEXT of this problem? What is that, in terms of the model?

Answer 7

that d= 0 ?

Answer 8

No, if t=0, what does d=? look at your equation:

d=420-65t

Answer 9

Remember, the d-intercept is the value of d, when t=0. What is that value, for THIS equation?

And what time is it when t=0?

Answer 10

0

Answer 11

because anything multiplied by zero = 0

Answer 12

d=420-65t

Put in t=0:

d=420-65(0)

Yes, anything multiplied by 0, =0. So when t=0, WHAT IS d?

Answer 13

d=0

Answer 14

0,420 ?

Answer 15

When t=0

what does d=?

I can't tell what you mean by 0,420.

Answer 16

Just tell me: when t=0, what does d=?

Answer 17

420 ?

Answer 18

wait d = 65

Answer 19

Im sorry im confused

Answer 20

Yes!! OK... now we are getting somewhere. :) so when t=0, d=420. Now remember, that's the d-intercept, right?

Answer 21

Oh crap, I thought you had it. lol. let's back up.

Answer 22

Seee I did have it, and u got me confused lol :)

Answer 23

d=420-65t

Put in t=0:

d=420-65(0)

As you said, anything x 0 = 0, so you have:

d=420-0=420

Got that?

Answer 24

Yes I got tht..

Answer 25

Nothing *I* said could have given you the idea that d=65 when t=0. ;)

OK, so the question is, "What is the practical meaning of the d-intercept?" You now know that the d-intercept=420, because that's what you get for d (distance from destination) when t=0.

Now remembering that t represents time, what does IT MEAN for t to be =0?

Answer 26

I don't get what you're asking?

Answer 27

t represents time. So when t=0, what time are you at "in the process" being modeled? When t=1, you are 1 hour in (1 hour has passed). When t=5, you are five hours in.

where are you when t=0? How much time has passed?