In an examination, 70% students passed in Physics, 80% students passed in Chemistry, 75% students passed in Mathematics and 85% students passed in Biology, and x% students failed in all the four subjects. What is the minimum value of x?

Let S be a set of all distinct numbers of the form $${p \over q}$$, where p, q$$\in$${1, 2, 3, 4, 5, 6}. What is the cardinality of the set S?

If $$A = \{ x \in R:{x^2} + 6x - 7 < 0\} $$ and $$B = \{ x \in R:{x^2} + 9x + 14 > 0\} $$, then which of the following is/are correct?

I. $$A \cap B = \{ x \in R: - 2 < x < 1\} $$

II. $$A/B = \{ x \in R: - 7 < x < - 2\} $$

Select the correct answer using the code given below.

Let R be a relation from A = {1, 2, 3, 4} to B= {1, 3, 5} such that R = {(a, b) : a < b, where a$$\in$$A and b$$\in$$B}. What is RoR^$$-$$1 equal to?