If the factory fills 10 cups of yogurt per second, it takes 1800/10=180 seconds to fill 1800 cups.
77 unicorns, because yesterday the ratio was 6:5 and today it is 3:4. If you add the numbers for both ratios together, you get 11 and 7. Finding the LCM of these two gives 77 (because 7 and 11 are both prime).
You find the LCM of the sums because when you find values based on ratios, you divide value by the sum of the ratio.
e.g. I have 100 fruits. The ratio of apples to oranges is 2:3. How many apples are there?
To solve this you'd add 2 and 3 (5), divide 100 by 5 (20), multiply that by 2 (40) because that's the ratio of apples to oranges.
In this case, you do the reverse. So If I have 77 unicorns, then yesterday there were (77/11 = 7, 7*6= 42, 7*5= 35) 42 green unicorns and 35 yellow. The sum of 42 and 35 is 77. If you do this process with the other ratio you'll get similar results as well.
6, I believe is the answer
I would say that this study is an experiment.
The car manufacturer wants to test some changes that he wants to implement in his cars, which is why he has two control groups (standard cars and cars with the new content) to test those changes out. This is a typical experiment and not an observation as he is not really observing much.
