National Test for Programs After Twelfth

In a college, the ratio of the number of students to teachers is 12:1 and the ratio of non-teaching staff to students is 1:60. Which of the following is the ratio of the number of teachers to the number of non-teaching staff?

X takes 4 hours to write 100 pages of a book and Y takes 6 hours to write 90 pages of the same book. In how much time can they write 200 pages working together?
Note: Assume that the same amount of effort is required for writing each page of the book.

A sum of Rs 20,000 is invested for 3 years at compound interest, compounded annually. If the rate of interest is 20% for the 1st year, 10% for the 2nd year and 5% for the 3rd year, then which of the following is the value of the interest accrued in 3 years?

There are 3 times as many buses as there are cabs in a city. In total, 10% of the buses are air-conditioned and 60% of the cabs are air-conditioned.
If there are only these 2 types of vehicles, what percentage of the vehicles in the city are air-conditioned?

If A = {1, 2, 3, 5, 7}, B = {3, 4, 5, 7} and C = {0, 4, 9}, then which of the following is