Two trains of 200 m and 100 m long are running parallel at the rate of 20 m/sec. and 22 m/sec. respectively. How much time will they take to cross each other, if the trains are running along the same direction? [#1132]
Q1. Two trains of 200 m and 100 m long are running parallel at the rate of 20 m/sec. and 22 m/sec. respectively. How much time will they take to cross each other, if the trains are running along the same direction? Q1. Two trains of 200 m and 100 m long are running parallel at the rate of 20 m/sec. and 22 m/sec. respectively. How much time will they take to cross each other, if the trains are running along the same direction?
(A) 120 sec (A) 120 sec
(B) 100 sec (B) 100 sec
(C) 60 sec (C) 60 sec
(D) 50 sec (D) 50 sec
Answer: (D) 50 sec Answer: (D) 50 sec
The difference of speed = 22m/s - 20m/s = 2m/s
As the train with speed 22m/s will cross the other, hence this train have to go the smallest length of the trains distance ahead of the other to cross completely.
Hence This train will be ahead of 100m with a speed of 2m/s.
Hence The time to cross each other will take = 100m / (2m/s)
= 50 secThe difference of speed = 22m/s - 20m/s = 2m/s
As the train with speed 22m/s will cross the other, hence this train have to go the smallest length of the trains distance ahead of the other to cross completely.
Hence This train will be ahead of 100m with a speed of 2m/s.
Hence The time to cross each other will take = 100m / (2m/s)
= 50 sec
Q2. At what percentage of simple interest does an amount of money double in 12 years? Q2. At what percentage of simple interest does an amount of money double in 12 years?
(A) (A)
(B) (B)
(C) (C)
(D) (D)
Answer: (C) Answer: (C)
P * * 12
= P * * 12
= P *
= P * 100%P * * 12
= P * * 12
= P *
= P * 100%
Q3. In a school with 10 teachers, one retires and immediately a new teacher of age 25 years joins. As a result, the average age of the teacher reduces by 3. The age of the retired teacher is Q3. In a school with 10 teachers, one retires and immediately a new teacher of age 25 years joins. As a result, the average age of the teacher reduces by 3. The age of the retired teacher is
(A) 55 years (A) 55 years
(B) 65 years (B) 65 years
(C) 58 years (C) 58 years
(D) 60 years (D) 60 years
Answer: (A) 55 years Answer: (A) 55 years
25 years + (3*10) years = 55 years25 years + (3*10) years = 55 years
Q5. What is the formula to calculate the area of a circle? Q5. What is the formula to calculate the area of a circle?
(A) A = πr2 (A) A = πr2
(B) A = 2πr (B) A = 2πr
(C) A = πd (C) A = πd
(D) A = 1/2πr2 (D) A = 1/2πr2
Answer: (A) A = πr2 Answer: (A) A = πr2
The formula to calculate the area of a circle is A = πr2, where A is the area and r is the radius of the circle.The formula to calculate the area of a circle is A = πr2, where A is the area and r is the radius of the circle.
Q6. Select the number pair in which the two numbers are related in the same way as 35 : 6. Q6. Select the number pair in which the two numbers are related in the same way as 35 : 6.
Q7. The ratio of the number of boys and girls in a school of 720 students is 7 : 5. How many more girls should be admitted to make the ratio 1 : 1? Q7. The ratio of the number of boys and girls in a school of 720 students is 7 : 5. How many more girls should be admitted to make the ratio 1 : 1?
Q8. Three fourth of a number is more than two third of the number by 5. Then the number is Q8. Three fourth of a number is more than two third of the number by 5. Then the number is