1. ThinkStock / BuzzFeed
Correct!
Wrong!

A quarter of the balls are green, so 25 greens. There are twice as many blues as greens, so 50 blues. There are one-fifth as many reds as blues, so 10 reds. Add them together and you get 85, so the remaining 15 must be white. Via ThinkStock
2. ThinkStock / BuzzFeed
Correct!
Wrong!

1430 - 1250 = 180. 180 ÷ 1250 = 0.144. 0.144 x 100 = 14.4.

3. ThinkStock
Correct!
Wrong!

28 ÷ 40 = 0.7.

4. ThinkStock / BuzzFeed
Correct!
Wrong!

You'd expect 7 out of 10 reds to give a relative frequency of 0.7.

5. Correct!
Wrong!

You multiply the ratios together, so it's (10 x 5) : (5 :4), or 50 : 36. Then you need to see if both sides can be divided by anything to give you the simplest version. In this case, dividing them both by 2 gives you 25 : 18.

6. ThinkStock / BuzzFeed
Correct!
Wrong!

The way to work it out is 9,000 ÷ 1.05^3 = 7,774.54.

7. ThinkStock / BuzzFeed
Correct!
Wrong!

24 ÷ 40 = 0.6, so less than 2/3rds.

8. ThinkStock / BuzzFeed
Correct!
Wrong!

There are three possible "starter and main" combinations, and six possible "main and dessert" combinations, for a total of nine.

9. ThinkStock / BuzzFeed
Correct!
Wrong!

There are nine possible combinations; three of them include jelly.

So it's 3/9 or 1/3.

10. ThinkStock / BuzzFeed
Correct!
Wrong!

You know that spruce trees + pine trees + 2 = fir trees. 27 fir trees and 16 pine trees have been sold. So 27 - 26 - 2 = 9.

11. ThinkStock / BuzzFeed
Correct!
Wrong!

The correct answer is 437,062, or 4.4 x 10^5.