István exchanged two car lottery tickets worth $5000 \mathrm{Ft}$ each. On the 20th day of the lottery quarter, he said to Kálmán: "Take over one of my books. If we win, we will share the prize as interest, in proportion to our stakes and the time elapsed." Kálmán gave him 4000 Ft the next day. - A month later, István borrowed 2500 Ft from László under the same conditions. - At the same time, Kálmán said to Miklós: "Give me 2000 Ft. I have 4000 Ft in a joint car lottery ticket. If it wins, we will split my share as if you had joined me at the same time." Miklós accepted the offer.

In the quarterly draw, both tickets won. One car was appraised at $60000 \mathrm{Ft}$, the other at $48000 \mathrm{Ft}$. During the distribution, István wanted to keep the first car. The others acknowledged that they would share the proceeds from the second car. It was only then that Miklós learned that Kálmán's stake had not been in the bet for the entire quarter, which would make their prize smaller. As compensation, Kálmán agreed to calculate Miklós's share as if his money had been in the bet from the beginning of the quarter.

However, after the second car was sold, only $42000 \mathrm{Ft}$ remained for distribution. How much did each of the four participants receive from this?
I. The prize must first be divided among István, Kálmán, and László, since Kálmán only made an agreement with Miklós regarding his expected share of the prize.

According to the estimates, the prize worth $108000 \mathrm{Ft}$ was in the deposit. There was a quarterly, i.e., 90-day interest of $10000 \mathrm{Ft}$, so from it, each of them received 12 fillér per deposited forint for each deposit day.

István had $10000 \mathrm{Ft}$ in the deposit for the first 20 days, $6000 \mathrm{Ft}$ for the next 30 days, and $3500 \mathrm{Ft}$ for the remaining 40 days, so he received

$$
20 \cdot 10000 + 30 \cdot 6000 + 40 \cdot 3500 = 520000 \text{ times } 0.12 \mathrm{Ft},
$$

which is 62400 Ft. Similarly,

Kálmán's share is $70 \cdot 4000 \cdot 0.12 = 33600 \mathrm{Ft}$,

László's share is $40 \cdot 2500 \cdot 0.12 = 12000 \mathrm{Ft}$.

The boys must have calculated this before they agreed that István would keep the more expensive car. Thus, they also agreed that István would receive an additional $2400 \mathrm{Ft}$ from the expected sale price of the second car.

II. After Miklós's $2000 \mathrm{Ft}$, Kálmán stated that the interest for 90 days would be $90 \cdot 2000 \cdot 0.12 = 21600 \mathrm{Ft}$, so Kálmán would have 12000 Ft left.

III. Since the amount to be divided turned out to be $1/8$ smaller than the estimate, each participant's agreed share was reduced by $1/8$. István received 2100 Ft, Kálmán and László each received 10500 Ft, and Miklós received $18900 \mathrm{Ft}$.

Note. Many contestants tried to interpret or slightly modify the problem in various ways. However, only what the participants agreed on, whether pairwise or collectively, should be considered in the distribution. This includes the estimates, the literal distribution limited to the second car's price, and even Kálmán's unilateral statement, as Miklós did not object.