Word learning

Karel decided to learn the selected words gradually. On the first day, he learned 2 times more than the fifth; on the second day 3, times more than the first; on the third day 1, time more than the first; on the fourth day 5, times more than the third; and on the fifth day, he learned only one selected word. How many choice words did Karel learn altogether?

Final Answer:

x =  21

Step-by-step explanation:

$$\begin{gathered} f=1 \\ a=2\cdot f=2\cdot 1=2 \\ b=3\cdot a=3\cdot 2=6 \\ c=1\cdot a=1\cdot 2=2 \\ d=5\cdot c=5\cdot 2=10 \\ x=a+b+c+d+f=2+6+2+10+1=21 \end{gathered}$$

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