## Task 1 - 290511

On April 30, Kerstin receives money as birthday gifts from several relatives. She now has exactly 35 marks in her piggy bank and resolves to diligently collect recyclables in the following months so that she can put exactly 5 marks into the piggy bank at the end of each month.

At the end of which month will there first be 55 marks in the piggy bank if her plan succeeds?
Due to $55-35=20$, Kerstin still needs exactly 20 marks to reach her goal. Since she wants to save 5 marks every month, she needs $20: 5=4$ exactly 4 more months for this.

The fourth month after April is August. The desired 55 marks will therefore be in the piggy bank for the first time at the end of August.