6. If a student buys 5 notebooks, 20 kn will remain, but if he buys 8 notebooks, 16 kn will be missing. How many kuna did the student have?
6. From the conditions of the problem, it follows that $8-5=3$ notebooks need to be paid for with $20+16=36 \mathrm{kn}$. 4 POINTS
This means the price of one notebook is $36: 3=12 \mathrm{kn}$. ..... 2 POINTS
At the end, the student had $5 \cdot 12+20=80 \mathrm{kn}$. 4 POINTS