Question

The probability of getting correct answer is x/5 and the probability of getting wrong answer is 2x/3.what is the vaue of x?

Answer 1

Let
Probability of getting correct answer =x/5---(1)
Probability of getting wrong answer =2x/3---(2)
(1) + (2) =1
x/5+2x/3=1

(3x+10x)/15=1
13x/15=1
x=15/13

Answer 2

Probability of getting correct answer = x/5

and of getting wrong answer = 2x/3

now 

probability of getting correct answer + incorrect answer = 1

x/5 +2x/3 = 1

3x+10x/15 = 1

13x=15

x = 15/13