2023 · Q114
Suppose that x and y are distinct variables that take values from (1, 2, 3, 4, 5, 6). What is the probability that the value of the expression xy+x+y is even?
General Mental Ability, Quantitative Aptitude and StatisticsAlgebra and data interpretation
- A1/ 2
- B1/3
- C1/4
- D1/5
Explanation
xy + x + y = (x+1)(y+1) - 1 is even exactly when (x+1)(y+1) is odd, i.e. when both x and y are even. With distinct draws from {1,2,3,4,5,6}, the probability is (3/6) x (2/5) = 1/5. Hence D.