Explanation:
remember 3 things
1. 3 = 3/1 (any integer is also a fraction of itself divided by 1).
2. 3 / 1/6 = 3/1 / 1/6 = 3/1 × 6/1 (dividing by a fraction is the same as multiplying with the upside-down fraction).
3 a/b × c/d = ac / bd. in our case 3/1 × 6/1 = 18/1 = 18