Question

Mr. Valenzuela drives a total of 180 miles in 3 hours.

.he drives 48 miles in the first 3/4 hour.
. he dives 52 miles in the next hour
what is his average speed, in a mile per hour (mph), in the last 1 1/4 hours?

Answer 1

To find Mr. Valenzuela's average speed during the last 1 1/4 hours (which is 1.25 hours), we need to first determine how many miles he has driven in the first 2 hours and how many miles remain to be covered in the total journey of 180 miles.

1. **Distance driven in the first 3/4 hour:** 48 miles
2. **Distance driven in the next hour:** 52 miles

Now we calculate the total distance covered in the first 1 3/4 hours (1 hour and 45 minutes):

\[
\text{Total distance in the first 1 3/4 hours} = 48 \text{ miles} + 52 \text{ miles} = 100 \text{ miles}
\]

Now, we subtract this distance from the total distance of 180 miles to find out how far he needs to drive in the last 1 1/4 hours:

\[
\text{Distance remaining} = 180 \text{ miles} - 100 \text{ miles} = 80 \text{ miles}
\]

Next, we need to calculate the average speed during that last 1 1/4 hours:

\[
\text{Average speed} = \frac{\text{Distance}}{\text{Time}} = \frac{80 \text{ miles}}{1.25 \text{ hours}}
\]

Calculating that gives:

\[
\text{Average speed} = 80 \div 1.25 = 64 \text{ mph}
\]

Thus, Mr. Valenzuela's average speed in the last 1 1/4 hours is **64 miles per hour (mph)**.