Question 1129805
Distance between houses = 18km
Brad's speed = 1.5km/h
Andrea's speed = 4.5km/h
Delay in time = 4hrs

Time that brad will take if he went to Andreas house:

time = distance/speed
"""Put in the values"""
time = 18km/(1.5km/h)
"""Solve"""
time = 12hrs

Time Andrea will take if she went to Brads house:

time = distance/speed
"""Put in the values"""
time = 18km/(4.5km/h)
"""Solve"""
time = 4hrs

We know that Brad has traveled for 4hrs as Andrea started to walk 4hrs later so:

Distance brad traveled in 4hrs:
Distance = Speed*Time
"""Put in the values"""
Distance = 1.5km*4hrs
"""Solve"""
Distance = 6km

We know that they meet each other so Andrea will have traveled 18km - 6km = 12km so:

Time = Distance/speed
"""Put in the values"""
time = 12km/(4.5km/h)
"""Solve"""
time = (8/3)hrs

Brad walked 6km away from his home and Andrea walked 12km away from her house to meet each other
Brad took 4hrs
Andrea took (8/3)hrs

It can be wrong. You should confirm by checking the answers in the back of your book. I am just a beginner.