Questions
The distances covered by each of two runners during the first 21 minutes of a race are
shown in the graph below. The time at which one runner passes the other is between
(A 2 minutes and 3 minutes
(B 6 minutes and 9 minutes
(C 9 minutes and 12 minutes 
(D 18 minutes and 21 minutes
                                             
                                          
                                          
                                       