This is similar to the one you posted previously,
Instead of using 10u as the distance, the distance is 210km.
Zainul had a 1 hour head start, and base on his speed, he travelled 45km.
So the remaining distance is 255 – 45 = 210 km
Ratio of distance travelled when they meet
Z : A : Total => 45 : 60 : 105 => 90 : 120 : 210
Using Zainul distance and speed,
Time taken = 90/45 = 2 hours
Since the above ratio and calculation is based on 1 hours later, it’s actually 3 hours from 8.30am. The time they will meet is 11:30am ##