Civil Services Examination · প্রশ্ন 36

There are four statements X, Y, Z and W. Their relations are as follows: If X is incorrect, then so is Z; if Y is incorrect, then W is correct; if W is correct, then X is incorrect. Which of the following is/are correct? I. If X is correct, then so is Y. II. If Z is correct, then it is not necessary that Y is correct. Select the answer using the code given below.

I only
II only
Both I and II
Neither I nor II

উত্তর দেখান ও ব্যাখ্যা

উত্তর: (A) I only

ব্যাখ্যা

Y incorrect → W correct → X incorrect, so by contrapositive X correct → Y correct (I). If Z is correct then X is correct (contrapositive of the first rule), so Y must be correct, making II false.