5) Since 2.8 syrup is needed for 2.2 milk and you need 3 milk, make it 3/2.2 = x/2.8 and cross multiply to get 3.82
6) 11 1/4, 11.25. Since 1/3 of an hour is 3.75, just multiply it by 3.
7) 4 4/5, 4.8. Since half of it took 2.4 you would multiply it by 2
8) 2. Since you can also cross multiply it. One trick I use is to compare the numbers to find which one is on the denominator and numerator. If it goes down, then I know the numerator is bigger
9) 5.5
10) 10.2