Hello, really lost!

Chuck and Dana agree to meet in Chicago for the weekend.

Chuck travel 143 miles in the same time Dana travels 128 miles.

If Chuck's speed is 3mph more than Dana's, and they travel the same length of time,

at what speed does Chuck travel?

We will use the familiar:

.Distance

.=

.Speed x Time

. . specifically, this variation:

.Time

.=

.Distance ÷ Speed

. ******
Let D = Dana's speed (in mph).

Then D + 3 = Chuck's speed.

Chuck drove 143 miles at D+3 mph.

.His time was: 143/(D+3) hours.

Dana drove 128 miles at D mph.

.His time was: 128/D hours.

. . . . . . . . . . . . . . . . . . . .143

. . . . . 128

Their times are equal:

. --------

. =

. -----

. . * . . . There!*
. . . . . . . . . . . . . . . . . . . D + 3

. . . . . D

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

****** How do we know which variation to use?

Read the problem again . . .

. . They have different

*distances* and different

*speeds*.

. . But their <u>times</u> are the same.

And <u>

*that</u>* is what we will equate . . . see?