A bag contains white,black and red balls only. A ball is drawn at random from the bag. if the probablity of getting a white ball is 3/10 and that of blue ball is 1/5 then find the probablity of getting a red ball. if the bag contains 20 black balls then find the total number of balls in the bag
Answers
Answer:
Step-by-step explanation:
Probability of a white ball being drawn is 3/10
Probability of a blue ball being drawn is 1/5. To make this easier to figure out, make the denominator of the 1/5 → 10
To do this you multiply the numerator (1) and the denominator (5) both by 2, so the probability of a black ball being drawn is 2/10
To find out the probability of a red ball being drawn, you add 2/10 (blue ball probability) to 3/10 (white ball probability) so you get 5/10.
10/10 is the total number of balls in the bag, so you subtract 5/10 from 10/10
10/10 - 5/10 = 5/10 (probability of red ball)
How to figure out total number of balls in the bag:
There are a total of 20 black balls in the bag, so you need to convert 2/10 (black ball probability) to 20 total, instead of 2.
To do this, you multiply both 2 and 10 (2/10) by 10 which is 20/100
The number of black balls is 20 out of 100 in the bag,
So the total number of balls in the bag is 100.