Question
A box contains (x + 3) black balls, 6 yellow balls, and
5 orange balls. If two balls are selected at random and the probability of selecting two orange balls is 10/153, what is the difference between the number of black balls and orange balls?Solution
5C2 / (x + 14) C2= 10/153 [(5 * 4) / (1 * 2)] / [(x + 14) (x + 13) / (1 * 2)] = 10/153 (2 * 153) = x2 + 14x + 13x + 182 306 = x2 + 27x + 182 x2 + 27x - 124 = 0 x2 + 31x – 4x – 124 = 0 X(x + 31) – 4(x + 31) = 0 (x – 4) (x + 31) = 0 x = 4, -31 (negative value will be eliminated) Required difference = 7 – 5 = 2 balls
At what temperature a body will not radiate any heat energy?
What is the boiling point of water at sea level?
Which one of the following is not a part of nerves?
A person rings a metallic bell near a strong concrete wall. He hears the echo after 0.3 s. if the sound moves with a speed of 340 m/s, how far is the wa...
Which of the following statement(s) is/are true?
I. During inhalation ribs move out
II. During exhalation ribs move in
Which of the following force holds protons and neutrons inside the nucleus of an atom?
A coil of N turns, and area A is rotated at angular velocity ω in a magnetic field B. Find the maximum induced emf if at t=0 the plane of coil is paral...
A positive charge is initially at rest and then allowed to move freely in a region where there is a uniform electric field. What happens to its electri...
What happens when light enters a glass slab from air?
What is the unit of electric current?
