Answer:
40
Explanation:
To find the least common denominator, you find the least common multiples of the denominators, which in this case is 20 and 8.
Tower method:
Start: |20, 8
4 |20, 8 -> 4 is a factor that 20 and 8 have in common
5, 2 -> 20/4 = 5, 8/4 = 2, those numbers do not have a common factor.
4 * 5 * 2 = 40.
The fractions with 40 as its denominator is 6/40 and 45/40.