Susie has 8 pieces of string 3 pieces are 7.8 inches long ,and 5 pieces are 9.2 inches long. how many inches of string does susie have altogether

Which of the following is not a subset of {1,2,3}?

Solve the formula ax+ by = c for x.

How many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.) how many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.)