Question
In a bag, there are three different colour balls namely
red, yellow and white. The sum of the number of yellow and red balls in the bag is equal to the number of white balls in the bag. The probability of picking two red balls from the bag is (3/38). If the total number of red, yellow and white balls in the bag is 20, then find out the number of yellow balls in the bag.Solution
In a bag, there are three different colour balls namely red, yellow and white. Let’s assume the number of red, yellow and white balls in the bag is ‘R’,’Y’ and ‘W’ respectively. The sum of the number of yellow and red balls in the bag is equal to the number of white balls in the bag. Y+R = W Eq.(i) If the total number of red, yellow and white balls in the bag is 20. R+Y+W = 20 Put Eq.(i) in the above equation. W+W = 20 2W = 20 W = 10 Put the value of ‘W’ in Eq.(i). Y+R = 10 Eq.(ii) The probability of picking two red balls from the bag is (3/38). [R(R-1)]/(20x19) = 3/38 [R(R-1)]/10 = 3/1 R(R-1) = 30 R2−R−30=0 R2−(6-5)R−30=0 R2−6R+5R−30=0 R(R-6)+5(R-6) = 0 (R-6) (R+5) = 0 So R = 6, -5 Here the value of ‘R’ cannot be negative. So R = 6 Put the vale of ‘R’ in Eq.(ii). Y+6 = 10 Y = 10-6 So the number of yellow balls in the bag = Y = 4
What does Galvanometer do?
Which of the following is a chemical change?
Which of the following processes is responsible for the rusting of iron?
Two billiard balls each of mass 0.02 kg moving in opposite directions with speed 5 m s−1 collide and rebound with the same speed. What is t...
At what temperature a body will not radiate any heat energy?
The study of the inheritance of traits in humans is called
Which part of the body is affected by tuberculosis (TB)?
The number of electrons present in Carbon is?
A mass m moves in a vertical circle of radius R under gravity. What is the minimum mechanical energy required to complete the circle?