Question 992301


At a constant rate, distance (d) is 15 km and time (t) is 30 minutes where d and t are in direct variation of each other. In other words, the distance Ana runs varies directly with the amount of time she has been running. The formula will be d = kt, k is the constant.


Assuming you want to determine the distance travelled per minute, the constant ratio is:


k = distance travelled/time = 15 km/30 minutes = 0.5 km/minute. 


Therefore, Ana travels 1/2 kilometer for every minute she runs.


Another way you can set up the problem through direct variation:


When d = 15, t = 30


d = kt --> 15 = 30k


15/30 = 30k/30 --> k = 1/2


Verify:

d = kt --> d = (1/2)t


15 = (1/2)*30 --> 15 = 15 is true.