Home
Class 14
MATHS
John gets on the elevator at the 14th fl...

John gets on the elevator at the 14th floor of a building and rides up at the rate of 84 floors per minute.At the same time, Vinod gets an on elevator at the 58th floor of the same building and rides down at the rate of 92 floors per minute. If they continue travelling at these rates, then at which floor will their paths cross?

A

38

B

36

C

32

D

35

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to determine the floor at which John and Vinod will meet as they travel in opposite directions in the building. ### Step-by-Step Solution: 1. **Define Variables:** - Let \( t \) be the time in minutes after they start moving. - John's starting floor: 14th floor. - Vinod's starting floor: 58th floor. 2. **Calculate John's Position:** - John moves up at a rate of 84 floors per minute. - After \( t \) minutes, John's position can be expressed as: \[ \text{John's position} = 14 + 84t \] 3. **Calculate Vinod's Position:** - Vinod moves down at a rate of 92 floors per minute. - After \( t \) minutes, Vinod's position can be expressed as: \[ \text{Vinod's position} = 58 - 92t \] 4. **Set Up the Equation:** - To find the floor where their paths cross, we set John's position equal to Vinod's position: \[ 14 + 84t = 58 - 92t \] 5. **Solve for \( t \):** - Rearranging the equation gives: \[ 84t + 92t = 58 - 14 \] \[ 176t = 44 \] \[ t = \frac{44}{176} = \frac{1}{4} \text{ minutes} \] 6. **Find the Crossing Floor:** - Now substitute \( t = \frac{1}{4} \) back into John's position equation: \[ \text{John's position} = 14 + 84 \left(\frac{1}{4}\right) = 14 + 21 = 35 \] ### Conclusion: John and Vinod will cross paths at the **35th floor**.
Promotional Banner

Topper's Solved these Questions

Similar Questions

Explore conceptually related problems

David gets on the elevator at the 11th floor of a building and rides up at the rate of 57 floors per minute. At the same time, Albert gets on an elevator at the 51st floor of the same building and rides down at the rate of 63 floors per minute. If they continue travelling at these rates, then at which floor will their paths cross? (a) 19th (b) 28th (c) 30th (d) 37th

From the ground floor a man comes up to the fourth floor of a building using a staircase. If the man comes up to the same floor using an elevator, neglecting friction, compare the work done by the man in the two cases.

The cost of flooring a rectangular room is Rs. 5698. The rate of flooring is Rs. 37 per square metre. If the room is 14 metres long, what is the breadth of the room?

There are 20 steps to go to the first floor of a building from the ground floor . A child starts climbing up from the first step of the ground level . Mother starts coming down from the fourth step from the floor level of the first floor . If both have started at the same time with same speed, at which step would they meet counting from the first steps from the floor level of the first floor ?

A ladder 20 ft long leans against a vertical wall. The top end slides downwards at the rate of 2 ft per second. The rate at which the lower and moves on a horizontal floor when it is 12 ft from the wall is

Length of a classroom is three times its height and its breadth is 2 1/2 times its height. The cost of white-washing the walls at the rate of Rs.1.60 per m^2 is Rs. 158.4 . Find the cost of tiling the floor at the rate of Rs. 10 per m^2