Question

Write two fractions where the LCD is 20, but the product of the denominators is not 20

Answer 1

Answer:
`(1)/(4)` and
`(1)/(10)`

Explanation:

To calculate the Least Common Denominator (LCD) of two fractions you must descompose each denominators into their prime factors and multiply the commons and non-commons with the largest exponent.

Let's write the following two fractions:

`(1)/(4)` and
`(1)/(10)`

The LCD is:

`4=2*2=2^2\\10=2*5`

`LCD=2^2*5\\LCD=4*5\\LCD=20`

So, we have two fractions where LCD is 20.

Let's verify that product of the denominators is not 20:

`4*10=40` (The product is not 20).