Challenging 6103

Jonas and Vojta went on a three-day hike on Friday. On the first day, they covered a fifth of the total route, on Saturday three-quarters of the challenging route, and had 20 km left for Sunday.
What percentage of the total route did the boys cover in the first two days?
What a long route the boys covered on Friday.
The total length of the three-day hike.

Correct answer:

a =  80 %
b =  20 km
c =  100 km

Step-by-step explanation:

$a=100\cdot (\frac{1}{5}+\frac{3}{4}\cdot (1-\frac{1}{5}))=80\%$

$$\begin{gathered} c/5+3/4\cdot (c-c/5)+20=c \\ 0.2c=20 \\ \frac{1}{5}c=20 \\ c=100 \\ b=c/5=100/5=20\text{km} \end{gathered}$$

c/5 + 3/4·(c-c/5) + 20 = c

4c = 400


c = 400/4 = 100

c = 100

Our simple equation calculator calculates it.

$c=100=100\text{km}$

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