4. Ivica, on the excursion, spends half of his money and an additional 10 kuna every day. In four days, he spends all his money. How much money did Ivica have?
4. We solve the task in reverse, i.e., we will determine how much money Ivica had at the beginning of the fourth, third, second, and first day.

Since on the fourth day Ivica spent half of his money and another 10 kuna, and ended up with no money, it follows that half of his money was 10 kuna, so at the beginning of the fourth day, he had $2 \cdot 10=20$ kuna.

When on the third day Ivica spent half of his money, he was left with $10+20=30$ kuna, so at the beginning of the third day, he had $2 \cdot 30=60$ kuna.