Question

A person travels by car from one city to another. She drives for 29.8 min at 78.9 km/h, 12.2 min at 83.5 km/h, 40.9 min at 44.9 km/h, and spends 10.6 min along the way eating lunch and buying gas.
Determine the distance between the cities
along this route.
Answer in units of km

Answer 1

You will make repeated use of: (A minutes) x (1 hour / 60 minutes) x (B km / hour). Then, for the lunch and gas, the person is not moving, so that particular value for A is 0. Then add up all four terms.

Answer 2

The keys to understanding this problem is 1) conceptualizing the problem as the addition of 4 line segments (the fourth is of length 0 and is just a point with no length), and 2) how to convert from one measurement to another by using identities (60 minutes = 1 hour). In multiplication, this identity is in actuality a "1" and multiplication by 1 preserves the same answer.

Answer 3

In the first factor for any of the 4 terms, minutes in the numerator will cancel with minutes in the denominator. The same will happen with "hour", so you will be left with just "km" as the unit of expression which ties in nicely as a length.

Answer 4

what your saying is kind of confusing

Answer 5

What is it you don't understand? How far did you get before getting confused?

Answer 6

Start with "She drives for 29.8 min at 78.9 km/h" and stop there. Figure that part out first before going further. The rest is just repeated addition of the other lengths, but don't do those until you do the first part first. Breaking the problem up helps.

Answer 7

@tcarroll010 thank you that helps and so after i do that i add all of them together?

Answer 8

(A minutes) x (1 hour / 60 minutes) x (B km / hour). Just plug the numbers in, can you?