In a 90-minute soccer match, 10% of the time is lost due to ball retention, 10% of the remaining time is lost due to fouls, and 10% of the time that remains is lost due to warnings. How many minutes of effective playing time will there be in the soccer match?

1. Problem Description

In a 90-minute soccer match, 10% of the time is lost due to ball retention, 10% of the remaining time is lost due to fouls, and 10% of the time that remains is lost due to warnings. How many minutes of effective playing time will there be in the soccer match?

2. Solution Steps

The initial total time is 90 minutes.

The time lost due to ball retention is $10\%$ of $90$ minutes, which is $0.10 \times 90 = 9$ minutes.

The remaining time after ball retention is $90 - 9 = 81$ minutes.

The time lost due to fouls is $10\%$ of the remaining time (81 minutes), which is $0.10 \times 81 = 8.1$ minutes.

The remaining time after fouls is $81 - 8.1 = 72.9$ minutes.

The time lost due to warnings is $10\%$ of the remaining time (72.9 minutes), which is $0.10 \times 72.9 = 7.29$ minutes.

The effective playing time is the time remaining after warnings, which is $72.9 - 7.29 = 65.61$ minutes.

3. Final Answer

The effective playing time is 65.61 minutes. The answer is D) 65,61.