Question
In a class of 30 students, the average height is 155 cm.
After one student leaves and five new students join, the class size becomes 34, and the new average height drops to 154.5 cm. Given that the total height of the five new students is 750 cm, determine the height of a student who is 2 cm taller than the student who left the school.Solution
ATQ,
Sum of height of class = 30 * 155 = 4650 4650 - x + 750 = 154.5 * 34 5400 -x = 5253 x = 147 Required height of the student = 147 + 2 = 149 cm
A, B, and C are working together on a project. A can complete the project alone in 15 days, B in 20 days, and C in 30 days. On the first day, A, B, and ...
The speed of a train is 36 km/hr and it takes 12 seconds to cross a man. Find the time taken by train to cross a platform if the ratio of the length of ...
- Maya has to go to the airport. If she drives at 36 km/h, she arrives 1.5 hours late. If she drives at 60 km/h, she reaches 45 minutes early. What is the di...
How much time a train 100 metres long running at the speed of 72 km/hr take to cross a bridge 180 metres in length?
- Two cyclists, Aman and Raj, start at the same time from the same place and travel to a common destination. If their speeds are in the ratio 7:5 and Raj tak...
A train has to cover a distance of 350 km in 25 hours. If it covers half journey in 3/5th time, then the speed of covering the remaining dist...
If a bicycle can cover 65 km in 10 hours while a car can cover 90 km in 5 hours then find the average speed of car.
Saket and Rakesh are brothers whose shops are located at a distance of 10km and 12km respectively from their home. Both of them start at the same time f...
A can complete a piece of work in 12 days, and B can complete the same work in 16 days. They work together for 4 days, and then A leaves. How many more ...
Two classmates R and S stand at points U and V respectively. R starts toward V from U at a speed of (x – 5) km/h. After 3 hours, S starts toward U fro...
Relevant for Exams:
