Answer: D) 50 years Explanation: Let Rajan's present age be 'x' years.=> Then his daughter's present age is = x/3 years.His mother's present age = 13x/9 yearsNow, according to the question,x + x/3 + 13x/9 = 125=> x = 125x9/25 = 45Therefore, required difference = 13x/9 - x/3 = 13x - 3x/9 = 10x/9=> 10 x 45/9 = 50 years.

Answer: B) always less than either of the original fractions Explanation: We can easily Answer this by taking some values.   The question states that the two fractions, each have values between 0 and 1.Let us say one of the fraction is 1/2 and the other fraction is 1/3 .The product of the two fractions is 1/2 x 1/3 = 1/6 . is lesser than both 1/2  and 1/3 .So, the correct answer is that the product is always less than either of the original fractions.

Answer: C) Vacuum Explanation: Sound waves cannot travel through a Vacuum.   A vacuum is an area without any air, like space. So sound cannot travel through space because there is no matter for the vibrations to work in.

Answer: B) 1/204 Explanation: Let A, B, C be the events of getting a white ball in first, second and third draw respectively, then   Required probability = PA∩B∩C  = PA PBA PCA∩B  Now, P(A) = Probability of drawing a white ball in first draw = 4/18 = 2/9 When  a white ball is drawn in the first draw there are 17 balls left in the urn, out of which 3 are white  ∴PBA=317  Since the ball drawn is not replaced, therefore after drawing a white ball in the second draw there are 16 balls left in the urn, out of which 2 are white.  ∴PCA∩B =216=18  Hence the required probability = 29×317×18=1204

Answer: D) China and England Explanation: The Opium Wars were two wars in the mid-19th century involving Anglo-Chinese disputes over British trade in China and China’s sovereignty. The disputes included the First Opium War (1839–1842) and the Second Opium War (1856–1860).