Barbie wants to make two dollars using dollars half dollars in quarters how many different ways can she make two dollars

I don't understand the question, but here goes. 
I think there is only 1 way, with 8 quarters.

There are 8 quarters, 40 nickels, 20 dimes and then there are 200 pennies

I hope this helps

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.