<PRE><B>Question 479240</B>
A group of runners participated in a 10-kilometer race. One-eighth of the runners completed the race in 40 minutes or less. Seven-twelfths of the runners needed between 40minutes and one hour to finish. The remaining 70 runners took one hour or longer to complete the race. How many runners participated in the race?
-------------------

n - n*(1/8 + 7/12) = 70
n - n*(3/24 + 14/24) = 70
n - 17n/24 = 70
7n/24 = 70
7n = 1680
n = 1680/7 = 240 runners
</PRE>