Question

Jaime has two fractions, 318 and 1315, that he needs to compare. He knows he will not be able to tell which is bigger until they have been rewritten with the same denominator. Which of the following shows both of these fractions rewritten with their least common denominator?

Answer 1

im assuming that you mean 3/8 and 13/5

so you find the LCM of 8 and 5 which is 40

3/8 = 15/40

13/5 = 104/40

Answer 2

Their least common denominator is 90.

Explanation:

Given : Jaime has two fractions,
`(3)/(18)` and
`(13)/(15)`, that he needs to compare. He knows he will not be able to tell which is bigger until they have been rewritten with the same denominator.

To find : Which of the following shows both of these fractions rewritten with their least common denominator?

Solution :

The two fractions,
`(3)/(18)` and
`(13)/(15)` to compare we make denominator same.

Taking LCM of denominator 15 and 18,

2 | 15 18

3 | 15 9

3 | 5 3

5 | 5 1

| 1 1

`LCM(15,18)=2* 3* 3* 5`

Now make denominator same,

Multiply and divide
`(3)/(18)` by 5,

`(3* 5)/(18* 5)=(15)/(90)`

Multiply and divide
`(13)/(15)` by 6,

`(13* 6)/(15* 6)=(78)/(90)`

Now, Comparing the fractions numerator 78 > 15

i.e.
`(78)/(90)>(15)/(90)`

So,
`(13)/(15)>(3)/(18)`

Therefore, Their least common denominator is 90.