+30 Angela drove 212 km. Her speed was 42 km/h for about 20 min, then about 95 km/h for most of the trip, and finally about 55 km/h for the last 12 min. How long did the trip take?
+592 Let's split this into 3 parts: the 42km/h part, the 95km/h part and finally the 55km/h part.
42km/h:
Since she drove for 20 minutes (a third of an hour), and she was driving at 42 km per hour, we can just take 42 ÷ 3 = 14 km.
95km/h:
Since we don't know how long she drove, we will save this for last.
55km/h:
She drove for 12 minutes (or one fifth of an hour), and she was driving 55 km per hour, we can take 55 ÷ 5 = 11 km.
Now putting them all together, she drove a total of 212 km, and we know that she drove 14 km at 42km/h, and 11 km at 55km/h.
212 - 14 - 11 = 187 km.
Now we know how far she drove at 95km/h, and to figure out how long she drove, let's make an equation.
\(\frac{95}{60} = \frac{187}{x}\) now cross multiply
\(95x = 11220\)
\(x = 11220 \div 95 ≈ 118.105\)
This means she drove for about 20 + 118 + 12 = 150 minutes. (150.105 approximately if decimal is needed)
