2. Two friends collected 300 stamps. One collected 5 per week, the other - 3. The second boy collected for 20 weeks longer than the first. How many days did each boy collect stamps?
2. 3) $20 \times 3=60 \text{m}$ - the second boy collected in 20 weeks;
2) $300-60=240 \text{m}$ - the boys collected during the time the first boy was collecting;
3) $5+3=8$ m - they collected per day;
4) $240: 8=30$ days - the first boy collected;
5) $30+20=50$ days - the second boy collected.

Answer: the first boy collected stamps for 30 days, and the second for 50.