Final answer:
The ratio $2.80: $1.60 can be simplified by converting to whole numbers and reducing by their greatest common divisor, resulting in a simplified fraction of 7/4.
Step-by-step explanation:
To write the ratio $2.80: $1.60 as a fraction in simplest form, first convert the amounts to whole numbers by getting rid of the decimal points. This can be done by multiplying each side by 100, resulting in the ratio of 280:160. Then, simplify the ratio by finding the greatest common divisor (GCD) of these two numbers. In this case, the GCD is 40. Therefore, divide each side of the ratio by 40 to simplify it.
The simplified ratio is 280/40 : 160/40, which simplifies to 7:4 when written as a fraction. Hence, the ratio of $2.80 to $1.60 in simplest form is 7/4.