Subject: mathqa
Question: ramu rides his bike at an average speed of 45 km / hr and reaches his desitination in 4 hours . somu covers the same distance in 6 hours . if ramu covered his journey at an average speed which was 9 km / hr less and somu covered his journey at an average speed which was 10 km / hr more , then the difference in their times taken to reach the destination would be ( in minutes ) .
Option: 
A: 23 minutes
B: 33 minutes
C: 23 minutes
D: 30 minutes
Answer: D