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
Q1. If the sum of five consecutive numbers is 190, then the lowest number amongst them is Q1. If the sum of five consecutive numbers is 190, then the lowest number amongst them is
Q2. What is the term for the result of multiplying a number by itself? Q2. What is the term for the result of multiplying a number by itself?
(A) Factor (A) Factor
(B) Product (B) Product
(C) Quotient (C) Quotient
(D) Square (D) Square
Answer: (D) Square Answer: (D) Square
The result of multiplying a number by itself is called a square, such as 4 × 4 = 16, which is denoted as 42 (four squared).The result of multiplying a number by itself is called a square, such as 4 × 4 = 16, which is denoted as 42 (four squared).
Q4. A 100 metre long train moving in a uniform speed of 20 m/sec crosses a bridge of length 1 km. The time taken by the train to cross the bridge is Q4. A 100 metre long train moving in a uniform speed of 20 m/sec crosses a bridge of length 1 km. The time taken by the train to cross the bridge is
Q6. A number was increased by 40% and thereafter decreased by 40%. The net change in the number in percentage is Q6. A number was increased by 40% and thereafter decreased by 40%. The net change in the number in percentage is
Q7. The LCM of two numbers is 40 and their HCF is 4. If the difference between the two numbers is 12, then the sum of the numbers is Q7. The LCM of two numbers is 40 and their HCF is 4. If the difference between the two numbers is 12, then the sum of the numbers is
(A) 20 (A) 20
(B) 24 (B) 24
(C) 28 (C) 28
(D) 32 (D) 32
Answer: (C) 28 Answer: (C) 28
X * (X-12) = 40 * 4
X = 20
X + (X-12) = 20 + 20 - 12 = 28X * (X-12) = 40 * 4
X = 20
X + (X-12) = 20 + 20 - 12 = 28
Q8. Two numbers are in the ratio 2 : 3 and the product of their HCF and LCM is 96. The sum of the two numbers is Q8. Two numbers are in the ratio 2 : 3 and the product of their HCF and LCM is 96. The sum of the two numbers is