Question 1074548
Let n be the number of 5-cent stamps. Then the number of 13-cent stamps is 2n+1; and the number of 8-cent stamps is 2n+1-6, or 2n-5. So:
5n+8(2n-5)+13(2n+1)=537
47n-27=537
47n=564
n=12
There are 12 5-cent stamps in the collection. &#9786;&#9786;&#9786;&#9786;