Answer:
4 weeks
Explanation:
Well since he rides his bike 15 kilometers every two period, we can assume that he rides his bike 7.5 kilometers a day. So:
Where x is the number of days he rides his bike.
So it will take him 20 days to ride his bike 150 kilometers.
Now all we have to do is divide the 20 days by 5 to show how many weeks it took:
It took him 4 weeks.