Question
A bag contains 30 white and some black balls. If the
probability of drawing a black ball from the bag is 1.4 times that of drawing a white ball, find the number of black balls in the bag.Solution
 Given, Number of white balls = 30 Let x be the number of black balls. Total number of balls in the bag = 30 + x Also, the probability of drawing a black ball from the bag is 1.4 times that of drawing a white ball. ⇒ x/ (30 + x) = 1.4[30/ (30 + x)] =5x = 7×30 ⇒ x = 42 Hence, the number of black balls in the bag = 42.
Reema’s income in March was four times what she earned in each of the other months of the year. What is the ratio of her income in March to her total ...
A, B and C has total 60 toffies with them. A has 25 toffies and the number of toffies with C is 5 less than that with B. How many...
Two vessels, A and B, contain mixtures of milk and water in the ratios 11:9 and 13:37, respectively. The quantities of mixtures in A and B are in the ra...
An amount of Rs. 2,100 is divided among D, E, and F in the ratio 5:4:6. Find the difference between the amount received by D and E together and E and F ...
- In a park, the ratio of adults to children is 7:5. If the number of adults was decreased by 21 and children increased by 14, then their numbers become equa...
A certain amount was divided among four people P, Q, R and S such that the amount obtained by S is 12.5% more than the amount obtained by Q. The amount ...
Sneha had 900 stickers. She gave 50% of them to Tina and Meena in the ratio of 4:5. What is the difference between the stickers Meena received and the n...
- A college has 720 students with a boy to girl ratio of 2:1. If the ratio of boys who passed to failed is 5:1 and for girls it is 3:2, find the total number...
There are 84 chocolates in a packet. The ratio of dark chocolates to milk chocolates is 3:2, and the ratio of dark chocolates to white chocolates is 6:5...
A factory manufactures two types of widgets, A and B, in the ratio of 4:5. If the production of widget A rises by 20% while the production of widget B d...
Relevant for Exams:
