Answer :
Answer: 2.5 hours or 150 minutes.
Step-by-step explanation:
We know that she drove a total of 212 km.
And we also need to remember the relationship:
Distance = Time*Speed.
We know that she drove at 42km/h for 20 mins, then the total distance traveled in that time is:
42km/h*(20min)
First we should rewrite the time in hours, we know that:
1 h = 60min
Then:
20 min = 20 min*(1h/60 min) = 0.33 h
Then the equation becomes:
42km/h*(0.33 h) = 13.86km
We also know that she drove at 55km/h for 12 mins at the end, the total distance traveled in this time is:
55km/h*(12 min)
Rewriting the time in hours we get:
12 min = 12 min*(1 h/60min) = (12 /60) h = 0.2 h
Then:
55km/h*(0.2 h) = 11 km
The total distance that we know that she traveled in these two intervals of time is:
11km + 13.86km = 24.86km
The difference between the total distance and this is:
212 km - 24.86km = 187.14 km
Then she drove a total distance of 187.14 km at the speed of 95km/h
The time that it took is:
Time = (187.14km)/(95km/h) = 1.97 h
Then the total time of the travel is:
1.97h + 0.33h + 0.2h = 2.5 hours
If we want the answer in minutes, we can remember that 1 hour equals 60 minutes, then 2.5 hours are:
2,5 hours = 2.5*60 min = 150 mins