Find the cardinal number of the following set: $\{x: x \text{ is a letter of the word } 'ASSASSINATION' \}$

If ${N_a} = \{ an : n \in N \} ,$ then ${N_3} \cap {N_4} = $

Range of the function $f(x) = \frac{x^2 + x + 2}{x^2 + x + 1}; x \in R$ is

Which of the following pairs of sets are not equivalent?

In a certain class,$72 \%$ of the students took Biology and $44 \%$ took Mathematics. If each student took at least one of Biology or Mathematics and $40$ students took both of these subjects,the total number of students in the class is:

In a class of $50$ students,$35$ opted for Mathematics and $37$ opted for Biology. How many have opted for both Mathematics and Biology? How many have opted for only Mathematics? (Assume that each student has to opt for at least one of the subjects).