Truck Journey Time

The truck driver left Prague at 7:20 a.m., took a twenty-minute break in Poděbrady, and reached Hradec Kralové at 8:55 a.m.
How long did the whole journey take (including a break)?
How long was the ride itself?

Result

a = 1:35 h
b = 1:15 h

Step-by-step explanation:

$$\begin{gathered} a_1=(8+\frac{55}{60})-(7+\frac{20}{60})=\frac{19}{12}\doteq 1.5833 \\ a=a_1=\frac{19}{12}=1.58333=1:35\text{h} \end{gathered}$$

$b=a_1-\frac{20}{60}=\frac{19}{12}-\frac{20}{60}=\frac{95}{60}-\frac{20}{60}=\frac{95-20}{60}=\frac{75}{60}=1.25=1:15\text{h}$

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