Can you check these percent proportion problems?

Question

1. 50 students got pizza at lunch. 20% of those got chocolate milk. How many students got chocolate milk?

50/n = 20/100
20n = 100*50
20n = 5000
n = 5000/20
n = 250 students

2. Mr. Ford has 45 fish in his aquarium. What is the number of blue fish if 40% of the fish are blue?

n/45 = 40/100
100n = 45*40
100n = 1800
n = 1800/100
n = 18 fish

3. In a survey 30 out of 40 people said they like carving pumpkins during all season. What is the percent of people who like to carve pumpkins?

30/40 = p/100
40p = 30*100
40p = 3000
p = 3000/40
p = 75%

4. In a dog park, 80% of the dogs were on leashes. If 20 dogs were on leashes, then how many dogs were in the park?

20/d = 80/100
80d = 20*100
80d = 2000
d = 2000/80
d = 25 dogs

Unit Rate/Ratios
1. Mr. Santana was buying some candy for his classes. When he went to buy some Crunch bars, he found 2 different packages:
3.6 oz for $1
11.5 oz for $2.50

Which is the better buy?
Answer: seems like it would 11.5oz because getting more in the bag. But, not sure how to put this is in a proportion.

Answer 1

1. You have to just multiply them, because it says 20% of those 50 students got milk, so
50 * 0.2 = 10 students
2. Yep
3. Yep
4. Yep
5. [Unit ratio]
What we'll do here is to get the cost per oz. Thus we divide $1 by 3.6 oz and $2.50 by 11.5 oz, then compare.
$1/3.6 = $0.278 / oz
$2.5/11.5 = $0.217 / oz

Thus the second option is better.

Hope this helps~ :3

Answer 2

Thanks!! Yes, this helps.