Question : The average of $n$ observations is 40. If one observation of value 80 is added, then the average of all the observations is 41. What is the value of $n$?

Option 1: 40

Option 2: 39

Option 3: 38

Option 4: 43

Question : If $\cos\theta=\frac{3}{5}$, then the value of $\sin\theta.\sec\theta.\tan\theta$ is:

Option 1: $\frac{9}{16}$

Option 2: $\frac{16}{9}$

Option 3: $\frac{3}{4}$

Option 4: $\frac{4}{3}$

Question : What is the least value of x so that the number 8x5215 becomes divisible by 9?

Option 1: 3

Option 2: 1

Option 3: 5

Option 4: 6

Question : The value of $\frac{2}{3} \div \frac{3}{10}$ of $\frac{4}{9}-\frac{4}{5} \times 1 \frac{1}{9} \div \frac{8}{15}+\frac{3}{4} \div \frac{1}{2}$ is:

Option 1: $\frac{29}{6}$

Option 2: $\frac{17}{9}$

Option 3: $\frac{14}{3}$

Option 4: $\frac{49}{12}$

Question : The value of $\frac{2}{3} \div \frac{3}{10}$ of $\frac{4}{9}-\frac{4}{5} \times 1 \frac{1}{9} \div \frac{8}{15}-\frac{3}{4}+\frac{3}{4} \div \frac{1}{2}$ is:

Option 1: $\frac{25}{6}$

Option 2: $\frac{14}{3}$

Option 3: $\frac{17}{9}$

Option 4: $\frac{49}{12}$