Quantitative Aptitude - Arithmetic Ability Questions

Ans.
Given that length of first train + length of second train = 660
Speed of first train : Speed of second train = 5:8 =5x : 8x
Time taken to cross the poll by two trains = 4:3 =4y:3y
Now ,
(5x*4y) + (8x*3y) = 660
44xy = 660
xy = 15
L1 - L2 = 24xy -20xy = 4xy = 60 m

7 × 5 = 35

35 – 1 = 34

Let the speed of the trains be x and y respectively
length of train1 = 47x
length of train2 = 31y
Relative speed= x + y
Time taken to cross each other = 33 s
=> 47x+31yx+y= 33
=> (47x + 31 y) = 33(x + y)
=> 14x = 2y
=> x/y = 2/14 = 1/7

 = 1:7

Time required will be in ratio = 5:4

B alone will do it in =16 days

I = Prt

Here to say which fraction is greater from the given options, the fraction with greater numerator with same denominator or smaller denominator with same numerator.

To find the greater fraction, among the given options, make the denominators same for the options by finding the LCM of all the denominators.

7/12, 9/16, 13/20, 32/80

Now, LCM of 12, 16, 20, 80 = 240.

Then,

140/240, 135/240, 156/240, 96/240

Here 

$$\begin{gathered} 156240 > 140240 > 135240 > 96240 \\ => 1320 > 712 > 916 > 3280 \end{gathered}$$

Hence, largest fraction = 13/20.

The given series is 15, 19, 27, 38, 55, 75

15

15 + 4 = 19

19 + 8 = 27

27 + 12 = 39

39 + 16 = 55

55 + 20 = 75

Hence, the odd number in the given series is 38.

Given   1.21x0.91.1x0.11

= 1.21x100x0.9x101.1x10x0.11x100

= 9

= 3.