Harry, hannah and howard are all going by train to london to watch the olympics. hannah departs on the 2: 15 pm train. harry's train journey takes 50% longer than howard's. harry departs on the 3: 00pm train. howard leaves 20 minutes after hannah and arrives at 3: 25 pm. when will harry arrive?

Hanna train departs at 2:15 pm , while harry departs at 3.00 pm  and Howard departs at 2:35 pm (20 minutes after Hannah). Howard arrives at 3.25 pm which means he takes 50 minutes. Harry trains takes 50% longer than Howard which is 1.5 × 50 = 75 minutes( 1 hr 15 minutes . Therefore harry arrives at 4.15 pm ( 3.00 + 1 hr 15 minutes). 
hence, the answer is 4.15 pm

First, calculate for the time that Howard leaves which is given to be 20 minutes later than Hannah. Hence, Howard left at 2:35 pm. The total time it took him to travel the distance is calculated by deducting 2:35 pm from 3:25 pm which will give us 50 minutes.

The number of minutes that Harry traveled would be equal to 1.5(50 minutes) which is equal to 75 minutes or equal to 1 hour and 15 minutes. If Harry departed by 3:00 pm, he will be able to reach his destination by 4:15 pm.

    4:15 pm