Quantitative Aptitude - Arithmetic Ability Questions

Let B's present age = x years. Then, A's present age = (x + 9) years.
(x + 9) + 10 = 2(x - 10)

 => x + 19 = 2x - 20

 => x =39.

The given number series is 120, 36, 6, 2, 1, 1

120

120/5 = 24 (not 36)

24/4 = 6

6/3 = 2

2/2 = 1

1/1 = 1

Hence, the odd man in the given number series is 24.

Let the sum be Rs.P.then
P(1+R/100)^3=6690…(i) and P(1+R/100)^6=10035…(ii)
On dividing,we get (1+R/100)^3=10025/6690=3/2.
Substituting this value in (i),we get:
P*(3/2)=6690 or P=(6690*2/3)=4460
Hence,the sum is rs.4460.

$$\begin{gathered} 13 x ? + 47 x 114 x 539 = 31100 x 2000 \\ ? = 378 x 3 \\ ? = 1134 \end{gathered}$$

Here the given number series is 3, 14, 36, 67, 113, 168

It follows a pattern that

3

3 + 1 x 11 = 3 + 11 = 14

14 + 2 x 11 = 14 + 22 = 36

36 + 3 x 11 = 36 + 33 = 69

69 + 4 x 11 = 69 + 44 = 113

113 + 5 x 11 = 113 + 55 = 168

Hence, the wrong number is 67.