# math

posted by on .

Over the river and through the woods to grandpa's house the smith grandchildren go. They drive 120miles to reach grandpa's house and the same distance back home.
1) It took 1.2hours to get halfway there. What is their average speed, in miles per hour, for the first 1.2hours of the trip? 120/2=60 so 60/112=50mph
50mph
2)The average speed for the remainder of the trip was 40mph. How long, in hours,did it take them to drive the remaining distance?120/40= 3hours
#)Traveling home the same route,the kids drove at an average rate of 55 miles per hour. After 2 hours their car broke down. How many miles were they away from home?55x2=110, since the total trip is 120 they were 10 miles away from home.
Are these correct? Thank you for checking my work

• math - ,

1. Yep

2. The remaining distance is is 120 - 60 = 60 miles (because the first 60 miles was already covered in 1.2 hours according to #1)
Speed is distance over time, or
v = d/t
Substituting,
40 = 60/t
t = 60/40
t = 1.5 hours

3. Yep

• math - ,

thank you, I see where I went wrong