q: The no. of girls in a class are seven times the no. of boys, which value cannever be the of total students?
Options:
(A) 3
(B) 5
(C) 8
(D) 9
(E) 11
a: OK... Let the boys are X, then girls are 7X, total = X+7X = 8X
So it should be multiple of 8, 30 is not a multiple of 8.
The answer is (C).

q: Find the odd man out
253, 136, 352, 326, 631, 244
Options:
(A) 326
(B) 136
(C) 352
(D) 631
(E) 531
a: OK... The sum all three digits comes to 10 except 326
The answer is (A).

q: An design manager has 10patterns of chairs & 5patterns of tables. In how many ways can he make a pair of table & chair?
Options:
(A) 20
(B) 40
(C) 50
(D) 90
(E) 100
a:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
OK... He has has ten patterns of chairs and eight patterns of tables
Hence, A chair can be arranged in 10 ways and
A table can be arranged in 5 ways
Hence one chair and one table can be arranged in 10 x 5 ways = 50 ways
The answer is (C).