Introduction to functions

Question

Tommy drives from town A to town B at a constant speed of 50km/h.

(a)write down an equation representing the relation between the driving distance D (in km) and the time taken t (in hour).

(b)Is D a function of t?

(c)Tommy leaves town A at 7:15 a.m. and arrives at a petrol station at 8:27a.m. Find the distance between town A and the petrol station.

Answer 1

(a)write down an equation representing the relation between the driving distance D (in km) and the time taken t (in hour).

rate x time = distance

50 km/ 1 hr(t) = D

(b)Is D a function of t?

Yes because for any given time and rate, there will be only one distance.

(c)Tommy leaves town A at 7:15 a.m. and arrives at a petrol station at 8:27a.m. Find the distance between town A and the petrol station.

The time is one hour and twelve minutes. 60 minutes in an hour, so, this is 1 1/5 hour, or 6/5 hour.

50 km/hr (6/5) = D

D = 60 miles