Question

pls answer this question pls​

Answer 1

for 1st question -

there are x red balls in bag

total balls are 20

so probability of getting a red ball in random draw = x/20

we need to find probability of not getting a red ball, which is equal to 1 - probability of getting a red ball

so required answer is 1 - x/20 = 19x/20

Now, 2nd question -

we have put 4 more red balls in the bag.

so total number of balls in bag is now 20 + 4 = 24

total number of red balls now is x + 4

according to question, the probability of getting a red ball now is 5/4 times of old probability (which is x/20)

new probability of getting red ball = x+4/24

now equating both probability with given conditions we get -

(x+4)/24 = (x/20)(5/4)

=> (x+4)/24 = x/16

=> 16x + 64 = 24x

=> 8x = 64

=> x = 8