Quantitative Aptitude - Arithmetic Ability Questions

The terms are alternatively multiplied by 1.5 and divided by 3. However, 18.5 does not satisfy it.

The pattern is -45, -35, -25, -15

The next number = 20-15= 5

The series given follow the pattern

+2, +2+4, +2+4+6, +2+4+6+8, +2+4+6+8+10,...

Here ? = 7 + 2 + 4 = 13.

Given fraction is 5 (2/7) - 3 (1/14) - 2 (1/14) - 1 (1/7) = ? + 3 (1/17) 

It can be written as 

(5 - 3 - 2 - 1) + (2/7 - 1/14 - 1/14 - 1/7) = ? +  3 (1/17) 

-1 + 0 - 3 (1/17) = ?

=> ? = -4 (1/17)

At 2 o'clock, the hour hand is at 2 and the minute hand is at 12, i.e. they are 10 min spaces apart. 

To be together, the minute hand must gain 10 minutes over the hour hand. 

Now, 55 minutes are gained by it in 60 min.

  10 minutes will be gained in 6055×10 min. = 101011 min. 

The hands will coincide at 101011 min. past 2.

The Sum of the digits in each number, Except 324 is 10.

114       131     165     216     ?      369

   +17      +34     +51     +68    +85

=> The missing number in the given Number series = 216 + 68 = 284.