Answer:
Step-by-step explanation:
Tadek has as much as the other two together, so has half the total. The other 20 zloty is split so Witek has 10 zloty less than Karol. If w represents the amount Witek has, then (20-w) is the amount Karol has, and the difference is ...
(20-w) -w = 10
10 = 2w . . . . . . . . add 2w-10
5 = w . . . . . . . . . . divide by 2
Witek has 5 zloty.