Find the LCM (least common multiple) of the denominators, and use that as the denominator for the two fractions.
Ex.

LCM (3, 4) is 12

=
Given that,
Shelley's pet food store sold one customer 5 peanut butter biscuits for $3. She sold another customer 7 beef treats for $4.20.
For peanut, the cost is ratio is

For beef, the ratio is

If we take cross product of these items,

It implies, that the sale is in true proportion. From the cross product, we find that it is equal.
Answer:
2.57 x 10^(-5)
Step-by-step explanation:
you have to move the comma sign in front of the first number considering 0 as a non-number.