While driving on the highway, Dave averages 60 miles per hour. In the city, he averages 30 miles per hour. On a trip to his grandmother's house, Dave drives 2 3/5 hours on the highway and 1 1/5 hours in the city.

The question: What is Dave's average speed for the entire trip to his grandmother's house? Round to the nearest tenth.

average speed = totaldistance/totaltime

since for each leg of the trip, distance = speed * time, we have

avgspeed = ((2 3/5 * 60)+(1 1/5 * 30))/(2 3/5 + 1 1/5)
= (156+36)/(3 4/5) = ?

So I got 50.52631..... and I rounded that to 50.5. Is this correct?

To find out the total distance traveled by Dave on his trip to his grandmother's house, we can use the formula:

Distance = Speed x Time

First, let's calculate the distance traveled on the highway. Dave drove 2 3/5 (or 13/5) hours on the highway, and his average speed was 60 miles per hour. So, the distance traveled on the highway is:

Distance on the highway = 60 miles per hour x 13/5 hours
Distance on the highway = (60 x 13) / 5 miles
Distance on the highway = 780 / 5 miles
Distance on the highway = 156 miles

Next, let's calculate the distance traveled in the city. Dave drove 1 1/5 (or 6/5) hours in the city, and his average speed was 30 miles per hour. So, the distance traveled in the city is:

Distance in the city = 30 miles per hour x 6/5 hours
Distance in the city = (30 x 6) / 5 miles
Distance in the city = 180 / 5 miles
Distance in the city = 36 miles

Finally, to find the total distance traveled, we need to add the distance on the highway and the distance in the city:

Total distance traveled = Distance on the highway + Distance in the city
Total distance traveled = 156 miles + 36 miles
Total distance traveled = 192 miles

Therefore, Dave traveled a total distance of 192 miles on his trip to his grandmother's house.