Backpack carrying

Alex, Charles, and Simon went on a trip at 6:45. They arrived at the finish line at 9:15. They carried one backpack with them and took turns after 20 minutes. Charles carried the first section, and at 8.30 by Simon.

a) Who carried the backpack in the second section?
b) How many minutes did Alex carry it, how many Charles, and how many Simon?
c) After how many minutes should the boys take turns so that everyone carries the backpack for the same length of time?
d) Suppose boys have backpacks, two-one lighter, the other heavier. Again, they will follow the same route from 6.45 to 9:15. Write down how they should take turns backpacking, to be fair.

Final Answer:

a = Ales
A =  60 min
K =  60 min
S =  40 min
c =  50 min
d =  25 min

Step-by-step explanation:

$a=Ales$

$$\begin{gathered} Karol==6:45 \\ Simon==7:05 \\ Ales==7:25 \\ Karol==7:45 \\ Simon==8:05 \\ Ales==8:25 \\ Karol==8:45 \\ Simon==9:05 \\ A=60=60\text{min} \end{gathered}$$

$K=60=60\text{min}$

$S=40=40\text{min}$

$c=(9\cdot 60+15-(6\cdot 60+45))/3=50\text{min}$

$d=50/2=25\text{min}$

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