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. ‘A’ starts his journey at 1:00 p.m. from a location P with a speed of 1 m/sec. ‘B’ starts his journey from the same location P and along the same direction at 1:10 p.m. with a speed of 2 m/sec. If ‘B’ meets ‘A’ at the location Q, then the distance PQ is : Q1. ‘A’ starts his journey at 1:00 p.m. from a location P with a speed of 1 m/sec. ‘B’ starts his journey from the same location P and along the same direction at 1:10 p.m. with a speed of 2 m/sec. If ‘B’ meets ‘A’ at the location Q, then the distance PQ is :
(A) 1.5 km (A) 1.5 km
(B) 1.75 km (B) 1.75 km
(C) 1.2 km (C) 1.2 km
(D) 1.25 km (D) 1.25 km
Answer: (C) 1.2 km Answer: (C) 1.2 km
A starts journey before B at a speed of 1 m/s. Hence A will be ahead of B
(10*60)s * 1m/s = 600m
Let A covers a distance of X after starting of B,
Then X + 600m = 2X
=> 2X - X = 600m
=> X = 600m
Hence B will cover a distance of 2X = 2 * 600m = 1200m = 1.2 kmA starts journey before B at a speed of 1 m/s. Hence A will be ahead of B
(10*60)s * 1m/s = 600m
Let A covers a distance of X after starting of B,
Then X + 600m = 2X
=> 2X - X = 600m
=> X = 600m
Hence B will cover a distance of 2X = 2 * 600m = 1200m = 1.2 km
An equilateral triangle is a triangle with three equal sides and angles, a regular polygon with three sides.An equilateral triangle is a triangle with three equal sides and angles, a regular polygon with three sides.
Q4. 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 Q4. 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 term for a line that divides a shape into two equal parts? Q5. What is the term for a line that divides a shape into two equal parts?
(A) Axis (A) Axis
(B) Median (B) Median
(C) Vertex (C) Vertex
(D) Bisector (D) Bisector
Answer: (D) Bisector Answer: (D) Bisector
A bisector is a line that divides a shape into two equal parts, like a line that cuts a triangle into two equal areas or a line that divides a circle into two equal parts (semi-circles).A bisector is a line that divides a shape into two equal parts, like a line that cuts a triangle into two equal areas or a line that divides a circle into two equal parts (semi-circles).
Q7. 98 toffees were distributed to some boys in a group. Each boy in the group got twice as many of the toffees as the number of boys. The number of boys in the group was Q7. 98 toffees were distributed to some boys in a group. Each boy in the group got twice as many of the toffees as the number of boys. The number of boys in the group was
(A) 5 (A) 5
(B) 7 (B) 7
(C) 10 (C) 10
(D) 14 (D) 14
Answer: (B) 7 Answer: (B) 7
7
=> x * 2x = 98
=> x2 =
=> x2 = 49
=> x = 77
=> x * 2x = 98
=> x2 =
=> x2 = 49
=> x = 7
Q8. 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 Q8. 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
Q9. What is the name of the mathematical concept that describes a value that never changes, like the ratio of a circle's circumference to its diameter? Q9. What is the name of the mathematical concept that describes a value that never changes, like the ratio of a circle's circumference to its diameter?
(A) Variable (A) Variable
(B) Constant (B) Constant
(C) Fraction (C) Fraction
(D) Decimal (D) Decimal
Answer: (B) Constant Answer: (B) Constant
A constant is a mathematical concept that represents a value that remains unchanged, like pi (π), which is approximately 3.14 and never changes.A constant is a mathematical concept that represents a value that remains unchanged, like pi (π), which is approximately 3.14 and never changes.
Q10. The product of two consecutive odd numbers is 19043. Which is the smaller number? Q10. The product of two consecutive odd numbers is 19043. Which is the smaller number?
