Question: Dawson earns $100 a week from his job. His income increased and now makes $110 a week. What is the percent increase?
Options:
(A) 5%
(B) 10%
(C) 15%
(D) 20%
(E) 25%
Answer: Increase = (10/100)*100 = (1/10)*100 = 10%.
The answer is (B).

Question: The average age of a class of 40 students is 15 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) 56 Years
(C) 32 Years
(D) 34 Years
(E) 49 Years
Answer: Total age of students is 40X15 = 600 Years
Total age inclusive of teacher = 41X (15+1) = 656
So, Teacher's age is 656-600 = 56 Yrs
There is a shortcut for these type of problems
Teacher's age is 15+(41X1) = 56 Years
The answer is (B).

Question: A man sells two articles for Rs.3600 each and he gains 30% on the first and loses 30% on the next. Find his total gain or loss?
Options:
(A) 9% loss
(B) 400
(C) 4000
(D) 324
(E) 8% LOSS
Answer: (30*30)/100 = 9%loss
The answer is (A).

Question: A boy runs 200 metres in 72 seconds. What is his speed ?
Options:
(A) 10 km/hr
(B) 14 km/hr
(C) 20 km/hr
(D) 12 km/hr
(E) 24 km/hr
Answer:
200/72 * 18/5 = 10 km/hr
The answer is (A).