## Solution
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
## What the question and answer could be
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)

## Solution
Out of 6 gaurds we have to select 3 -> selection means we use C -> so 6C3
Out of 3 forwards we have to select 2 -> selection means we use C -> so 3C2
Total ways = 6C3 x 3C2 = 60
## What the question and answer could be
9 basketball players are trying out to be on a newly formed basketball team. Of these players, 5 will be chosen for the team. If 6 of the players are guards and 3 of the players are forwards, how many different teams of 3 guards and 2 forwards can be chosen?
Options:
(A) 23
(B) 30
(C) 42
(D) 60
(E) 126
(D)

## Solution
10^2 - 20 = 80
20^2 - 30 = 370
30^2 - 40 = 860
40^2 - 50 = 1550
50^2 - 60 = 2440
60^2 - 70 = 3530.
## What the question and answer could be
80 370 860 ? 2440 3530
Options:
(A) 900
(B) 840
(C) 750
(D) 860
(E) 1550
(E)

## Solution
Speed = 45 * 5/18 = 25/2 m/sec
Total distance covered = 510 + 140 = 650 m
Required time = 650 * 2/25 = 52 sec
## What the question and answer could be
A train 510 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
Options:
(A) 40
(B) 52
(C) 26
(D) 21
(E) 14
(B)