Quantitative Aptitude - Arithmetic Ability Questions

Let the total number of children be x. 

Then, x * (20% of x) = 405  

=> x * 20x/100 = 405 

15x2 = 405 

=> x=45 

Number of sweets received by each child = 20% of 45 = 9.

In this type of problems the formulae is 5x-30×1211
x is replaced by the first interval of given time Here i.e 8
5*8-30*1211
= 12011min

Therefore the hands will be in the same straight line but not
together at 12011 min.past 8.

Here the given number series is 0, 3, 8, 15, 24, ?

The next number in the given series can be found such a way that the number series follows a pattern,

$$\begin{gathered} 22 - 4 = 0 \\ 32 - 6 = 3 \\ 42 - 8 = 8 \\ 52 - 10 = 15 \\ 62 - 12 = 24 \\ 72 - 14 = 35 \\ Hence, the next number in the iven series is 35. \end{gathered}$$

Let the number be x, Then 

75% of x + 75 = x 

=> x - 75x/100 =75 

=> x =  300 .

Angle traced by the hour hand in 6 hours=(360/12)*6

Here the given series is 123 112 133 112 143

It follows a pattern that,

123

123 - 11 = 112

112 + 21 = 133

133 - 31 = 102 (not 122)

102 + 41 = 143

Hence, the odd man in the given number sequence is 122 instead of 102.