shruti93 wrote:2. If there are 25 balls in a bag of either red blue or white color and each ball is numbered from 1 to 10. How many balls are either red or white

1) p(white and even)=0
2)p(w)- p(e) =0.2

OA:C

A few things:

First, when posting questions, please use the spoiler function to hide the correct answer. This will allow others to attempt the question without seeing the final answer.

Second, are you certain that your wrote the question correctly? It looks very similar to the question below, except the part in green is different

Each of the 25 balls in a certain box is either red, blue, or white, and has a number from 1 to 10 painted on it. If one ball is to be selected at random from the box, what is the probability that the ball selected will either be white or have an even number painted on it?

1) The probability that the ball will both be white and have an even number on it is 0.

2) The probability that the ball will be white minus the probability that the ball will have an even number painted on it is 0.2.

Target question: What is the value of P(white or even)?

To solve this, we need P(A or B) = P(A) + P(B) - P(A & B)
So, P(white or even) = P(white) + P(even) - P(white & even)

Statement 1: P(white & even) = 0
We can add this to our probability equation to get: P(white or even) = P(white) + P(even) - 0
Still need P(white), and we need P(even)
INSUFFICIENT

Statement 2: P(white) - P(even)= 0.2
We have no idea about the sum of P(white) and P(even), and we don't know the value of P(white & even)
INSUFFICIENT

Statements 1 and 2 combined:
Given P(white) - P(even)= 0.2 does not tell us the individual values of P(white) and P(even), and it doesn't tell us the value of P(white) + P(even).

So, since we can't determine the value of P(white) + P(even) - P(white & even), the statements combined are not sufficient.

Answer: E

Cheers,
Brent

shruti93 wrote:SORRY THE RED OR WHITE WAS A TYPO. AND I USED THE EXACT SAME LOGIC, AND GOT E. BUT THE ANSWER WAS C.:/

If the question reads "white or even," then the answer is most definitely E. You might want to recheck the source.

Cheers,
Brent