Question
A bag contains 19 white and some black balls. If the
probability of drawing a black ball from the bag is twice that of drawing a white ball, find the number of black balls in the bag.Solution
Given, Number of white balls = 19 Let x be the number of black balls. Total number of balls in the bag = 19 + x Also, the probability of drawing a black ball from the bag is twice that of drawing a white ball. ⇒ x/(19 + x) = 2[19/(19 + x)] ⇒ x = 38 Hence, the number of black balls in the bag = 38.
Two different alloys contain steel and aluminum in the ratios of 11:4 and 2:13, respectively. In what proportion should these two alloys be combined to ...
The sum to n terms of the series 1 + 1 + 3 + 1 + 3 + 5 + 1 + 3 + 5 + 7 …………………… is
If a, b, c are in geometric progression and a + b + c = 14, a² + b² + c² = 84, find a, b, c.
The current age of Anupama is 25% greater than Chinky's age. Four years ago, the ages of Beena and Chinky were in the ratio of 4:...
3600, 600, 120, 30, 10, ?
The first odd number is 1, second is 3, third is 5 and fourth is 7 and so on, then find the 188th odd number?
If the median and mode of a data set are 6 and 12 respectively, then find the mean of the data.
What is least number which when successively divided by 6, 4 and 4 leaves a remainder 5, 3 and 3 respectively?
The sum of total surface area of two cubes is 1248-centimeter square. If the product of the length of their edges is 96 centimeter square. Find the diff...
Pipe ‘A’ and pipe ‘B’ can fill a cistern in 20 minutes and 15 minutes respectively. Pipe ‘C’ alone can empty the cistern in 12 minutes. If a...
