Quantitative Aptitude - Arithmetic Ability Questions

87)13601(156
       87
       -----
       490
       435
        -----
        551
        522
         -----
         29
         -----
Required number is 29.

As the ratio of their present ages is 3 : 4 , let their present ages be 3X and 4X.

So, 5 years ago, as the ratio of their ages was 5 : 7, we can write  (3x-5) : (4x-5) = 5 : 7. Solving, we get X = 10. Hence, their present ages are 3X = 30 and 4X = 40

Required number of ways = (7C5*3C2) = (7C2*3C1) = 63

The given number series 22, 26, 42, 78, 142, 244 follows a pattern that,

$$\begin{gathered} 22 \\ 22 + 22 = 22 + 4 = 26 \\ 26 + 42 = 26 + 16 = 42 \\ 42 + 62 = 42 + 36 = 78 \\ 78 + 82 = 78 + 64 = 142 \\ 142 + 102 = 142 + 100 = 242 \end{gathered}$$ 

Hence, the odd one in the given number series is 244.