Question
The mean weight of 'w' students in a classroom is 42 kg.
When the class teacher, weighing 61.5 kg, is added to the group, the average weight increases by 0.5 kg. Determine the number of students in the class.Solution
ATQ, Total weight of students = 42w kg Total weight of students including class teacher = 42.5 × (w + 1) kg 42w + 61.5 = 42.5 × (w + 1) 42w + 61.5 = 42.5x + 42.5 0.5w = 19 w = 38 Required number of students = 38
A sum of Rs. 'Y' was invested for 7(1/4) years at simple interest of 8(2/5)% p.a. such that the simple interest received was Rs. 5,115.60. Find the si...
If a man rides a bicycle at a speed of 50 km/h for 2 hours and at a speed of 40 km/h for the next 4 hours then what will be the average speed?Â
Let A be a 3 × 3 matrix such that |A ∣ =4. Then ∣ adj(adj(A)) ∣ equals:
The ratio of ages of A and B is 4:3. If A is 5 years older than B, find the age of B.
A can complete a piece of work in 12 days, B in 18 days, and C in 36 days. They all work together for a few days, after which A leaves. B and C continue...
In a triangle ABC, the sides are AB = 15 cm, BC = 20 cm, and AC = 25 cm. Find the area of the triangle using Heron’s formula.
"Arjun" can complete a task on his own in 20 days. "Bhuvan" requires 5 days more than "Chirag" to finish the same task, where "Ch...
The speed of train X is 25% more than the speed of train Y. The time taken by train X to cover P km is z hours, and train Y covers the same distance in ...
The efficiency of P is 20% more than the efficiency of Q, and the efficiency of R is 80% of the efficiency of Q. If P starts with 5/4 of his efficiency ...
Relevant for Exams:
