Question

Dave drove 55 mph for part of the trip and 60mph for the rest. The 245 mile trip took him 4 hours 12 minutes. How long did the 2nd part of the trip take? How far did he drive during the 2nd part of his trip?

Answer 1

Answer:

Dave drove 168 miles during the 2nd part of the trip

Step-by-step explanation:

1. Let's review the information given to us to answer the question correctly:

Speed of Dave for part of the trip = 55 mph

Speed of Dave the rest of the trip = 60 mph

Total time of the round trip = 4 hours 12 minutes

Total distance of the trip = 245 miles

2. How far did Dave drive during the 2nd part of his trip?

Let's recall that the formula of speed is:

Speed = Distance/Time, therefore Distance = Speed * Time

x = Time of part of the trip

4 hours 12 minutes - x = Time of the rest of the trip

4.2 hours - x = Time of the rest of the trip

Now, we can write solve for x, this way:

55 * x + 60 (4.2 - x) = 245

55x + 252 - 60x = 245

-5x = 245 - 252

-5x = -7

x = -7/-5 = 7/5 = 1.4 ⇒ 4.2 - x = 2.8

1st part of the trip = 55 * 1.4 = 77 miles

2nd part of the trip = 2.8 * 60 = 168 miles

Dave drove 168 miles during the 2nd part of the trip and 77 miles during the 1st part