## 2. Traffic Light

The traffic light operates as follows: the green light shines for 17 seconds, yellow for 4 seconds, red for 11 seconds, yellow for 4 seconds, then green again for 17 seconds, yellow for 4 seconds, red for 11 seconds, yellow for 4 seconds, and so on throughout the entire day. How many minutes will the green light shine during one full day?

Result: $\quad 680$
## Solution.

One cycle of green - yellow - red - yellow lasts $17+4+11+4=36$ seconds.

Since 1 hour has 3600 seconds, the cycle repeats $3600: 36=100$ times in one hour.

Since one day has 24 hours, there are 2400 cycles in one day.

In each cycle, the green light shines for 17 seconds, so in one day it shines $2400 \cdot 17=40800$ seconds, which is $40800: 60=4080: 6=680$ minutes.