A competitor is running in a 25km race. For the first 15km, she runs at a steady rate of 12km/h. After completing 15km, she slows down and it is now observed that she takes 20% longer to complete each km than she took to complete the previous km.
(a)Find the time, in hours and minutes, the competitor takes to complete the first 16km of the race.
(b) the time taken to complete the rth km in u, hours,
Show that, for 16 greater than or equal r greater than or equal to 25, ur = 1/12(1.2)^r-15
(c) using the answer to b, or otherwise, find the time, to the nearest minute, that she takes to complete the race...
I cannot sovle these..
Part a) The first 15 km is easy, no? t = d / v. So 1 hr 15 min for the first 15 km. Each of these 1 kilometers was completed in, using t = d /v and d = 1 km, 5 min. The 16th kilometer is 20% longer than 5 minutes. should it be like 20/100*5 but it's giving me the wrong ans? HELPP:(
