Let the probability that A and B speak truth be P(A) and P(B) respectively. Therefore, P (A) = $\frac{60}{100}$ = $\frac{3}{5}$ and P (B) = $\frac{90}{100}$ = $\frac{9}{10}$ A and B can contradict in stating a fact when one is speaking the truth and other is not speaking the truth. Case 1: A is speaking the truth and B is not speaking the truth. Required probability = P (A) × 1 - P (B) = $\frac{3}{5} \times \left( 1 - \frac{9}{10} \right)$ = $\frac{3}{50}$ Case 2: A is not speaking the truth and B is speaking the truth. Required probability = 1 - P (A) × P (B) = $\left( 1 - \frac{3}{5} \right)$ × $\frac{9}{10}$ = $\frac{9}{25}$ ∴ Percentage of cases in which they are likely to contradict in stating the same fact = $\left( \frac{3}{50} + \frac{9}{25} \right)$ × 100% = $\left( \frac{3+18}{50} \right)$ × 100% = 42% From case 1, it is clear that it is not necessary that the statement of B will carry more weight as he speaks truth in more number of cases than A.