q: The average age of a class of 39 students is 15 years. If the age of the teacher be included, then the average increases by 3 months .Find the age of the teacher.
Options:
(A) 22
(B) 25
(C) 8
(D) 27
(E) 19
a: OK... Sum of the ages of the students = 3915 = 585
New average = 15 years 3 months = 15 + 1414 year
Sum of the ages of students and teacher = 4015141514 = 40614614 = 610
Teacher age = 610 585 = 25 years.
The answer is (B).

q: A no. when divided by the sum of 555 and 445 gives 2times their difference as quotient & 10 as remainder. Find the no. is?
Options:
(A) 220010
(B) 145778
(C) 220110
(D) 235467
(E) 220001
a: OK... (555 + 445) * 2 * 110 + 10 = 220000 + 10 = 220010
The answer is (A).

q: How much more would Rs.30000 fetch, after two years, if it is put at 20% p.a. compound interest payable half yearly than if is put at 20% p.a. compound interest payable yearly?
Options:
(A) 482
(B) 725
(C) 992
(D) 837
(E) 723
a:
OK... 30000(11/10)4 - 30000(6/5)2 = 723
The answer is (E).