## Solution
70 + 80 = 150 * 5/18 = 125/3 mps
D = 150 + 100 = 250 m
T = 250 * 3/125 = 6 se
## What the question and answer could be
Two trains are moving at 80 kmph and 70 kmph in opposite directions. Their lengths are 150 m and 100 m respectively. The time they will take to pass each other completely is?
Options:
(A) 4 sec
(B) 5 sec
(C) 6 sec
(D) 7 sec
(E) 8 sec
(C)

## Solution
In 30 minutes the man would have droven 20 miles, when his wife starts. Now both are driving in the same direction. So speed of wife related to man is 10(50-40) miles/hr. So wife will cover 20 miles in 2 hours to meet the man.
## What the question and answer could be
A man drives at a speed of 40 miles/hr. His wife left 30 mins. late with 50 miles/hr speed. when will they meet ?
Options:
(A) 1 hours
(B) 2 hours
(C) 3 hours
(D) 4 hours
(E) 5 hours
(B)

## Solution
Distance traveled by Eddy = 600 km
Time taken by Eddy = 3 hours
Average speed of Eddy = 600/3 = 200 km/hour
Distance traveled by Freddy = 360 km
Time taken by Freddy = 4 hours
Average speed of Freddy = 360/4 = 90 km/hour
Ratio of average speed of Eddy to Freddy = 200/90 = 20/9
## What the question and answer could be
Eddy and Freddy start simultaneously from city A and they travel to City B and City C respectively. Eddy takes 3 hours and Freddy takes 4 hours to complete the journey. If the distance between City A and City B is 600 kms and City A and City C is 360 kms. What is the ratio of their average speed of travel? (Eddy: Freddy)
Options:
(A) 8/3
(B) 3/8
(C) 8/5
(D) 5/8
(E) 20/9
(E)

## Solution
Probability of getting red ball from bag1 and then red from bag 2 = 3/5*5/10 = 15/50
Probability of getting black ball from bag1 and then red from bag 2 = 2/5*4/10 = 8/50
Now comes the condition, hence apply conditional probability:
P(Red)/ P(Red + Black)
(15/50)/(15/50+8/50) = 15/50 /23/50 = 15/23.
## What the question and answer could be
A bag contains 3 red and 2 black ball. Another bag contains 4 red and 5 black balls. A ball is drawn from the first bag and is placed in the second. A ball is then drawn from the second. What is the probability that this draw of red ball is due to the drawing of red ball from the first bag ?
Options:
(A) 3/5
(B) 2/5
(C) 4/25
(D) 3/10
(E) 15/23
(E)