Question

She needs to build a line of dominoes 21 and 1/4 in a long with each domino spaced 1 and 1/4 in. apart. How many will she need?

Answer 1

17 dominoes

Explanation:

21 and 1/4 in divided by how far they need to be spaced apart, 1 and 1/4 in, is equal to 17 dominoes.