Quantitative Aptitude - Arithmetic Ability Questions

Findout the odd word/letters/number/number pair from the given alternatives.
23 : 8 : : 62 : ?

Train A takes 45 minutes more than train B to travel a distance of 450 km. Due to engine trouble speed of train B falls by a quarter, so it takes 30 minutes more than Train A to complete the same journey. What is the speed of Train A (in km/hr)?

Seven years from now Virat will be twice as old as Mohinder. Five years ago Mohinder's age was one year less than 2/5 of Virat's age. What is Virat's present age?

At 9.5% simple interest per annum a sum of money became Rs. 942 in 6 years. The sum initially invested was:

A shopkeeper allows 25% discount on the marked price of an article and he suffered a loss of 15%. What will be the profit percent if the article is sold at marked price?

If A = 2B = 4C; what is the value of A : B : C?

$$\begin{gathered} 3x2-14x+16=0 \\ 5y2-16y+12=0 \end{gathered}$$

Find the compound interest on Rs. 62500 at 21% per annum for 1.5 years.