Question: Ruel has four books of 10 stamps and six books of 15 stamps. How many stamps does Ruel have?
Solution:
Ruel has a total of 4 x 10 = 40 stamps from the four books.
He also has 6 x 15 = 90 stamps from the six books.
Therefore, he has a total of 40 + 90 = 130 stamps.
Answer: 130