Total age of students is 22X10 = 220 Years
Total age inclusive of teacher = 23X (10+1) = 253
So, Teacher's age is 253-220 = 33 Yrs
There is a shortcut for these type of problems
Teacher's age is 10+(23X1) = 33 Years
The average age of a class of 22 students is 10 yrs. if the teacher's age is also included, the average increases by one year. Find the age of the teacher
Options:
(A) 30 Years
(B) 31 Years
(C) 33 Years
(D) 34 Years
(E) 49 Years
(C)

Total ways to choose 4 employees from 8 employees = 8C4
Two women = 4C2
Two Men = 3C2
P = (5C2 * 3C2)/8C2 = 18/70 hence
A small company employs 3 men and 4 women. If a team of 4 employees is to be randomly selected to organize the company retreat, what is the probability that the team will have exactly 2 women?
Options:
(A)  1/14
(B)  1/7
(C)  20/70
(D)  18/70
(E)  1/2
(D)

Required sum = (31 + 37 + 41 + 43 + 47) = 199
Note: 1 is not a prime number

What is the sum of all the prime numbers greater than 30 but less than 50?
Options:
(A) 126
(B) 199
(C) 198
(D) 188
(E) 122
(B)