For #2, you have to convert the mixes fractions to improper fraction so you can divide them. To do that, multiply the denominator by the whole number, and add the numerator. Then use that number as the new numerator.
2 x 3 = 6 6 + 1 = 7/2
4 x 1 = 4 4 + 1 = 5/4
Then to find the unit rate, you divide. To do that, use the saying "keep, change, flip".
7/2 • 4/5
Then multiply!
7 x 4 = 28 2 x 5 = 10 28/10
Then divide 28 by 10 to turn it back into a mixed fraction.
2 8/10
Hope I could help! If I have time later I'll try to help you solve the rest :D
You can find a unit rate when given a rate by dividing the the second number in the rate (if you had 3:4, you would divide 4) by the same number. (in the problem I gave you, you would divide 4 by 4 to get 1 then divide 3 by 4.) Then you would have the unit rate. Sorry if that didn't make any sense.
