Bank PO Questions

Speed on return trip = 150% of 50 = 75 km/hr.

Average speed = (2 x 50 x 75)/(50 + 75) = 60 km/hr.

The term gram formula mass is synonymous with molecular mass. So, to get this, we must add molar mass of all the elements in this compound.

Given compound is Lithium Sulphate - Li2SO4

Elemental calculation ::

Li  -  Lithium   -   6.941    -     2   -   13.88200 %
S  -  Sulfur     -    32.065   -    1   -   32.065 %
O  -  Oxygen   -   15.9994  -    4   -   63.9976 %

Now, total = 12.6264 + 29.1647 + 58.2090 = 109.9446 

Hence, the gram formula mass of Li2SO4 = 109.9446.

The given letter equation implies that, 

7 C in the R = 7 Colours in a Rainbow.

It follows the rule that

1

2x2  

3x3x3  

4x4x4x4  

5x5x5x5x5 

So the missing number is 4x4x4x4 = 256.

We can initially arrange the six boys in 6! ways.
Having done this, now three are seven places and six girls to be arranged. This can be done in ⁷P₆ ways.

Hence required number of ways = 6! x ⁷P₆

The first train covers 180 kms in 5 hrs

=> Speed = 180/5 = 36 kmph

Now the second train covers the same distance in 1 hour less than the first train => 4 hrs

=> Speed of the second train = 180/4 = 45 kmph

Now, required difference in distance in 1 hour = 45 - 36 = 9 kms.

Here given soldier shots 7 shots in 12 min

=> 1 shot doen't take any time in 12 min 

=> Only 6 shots take 12 min 

12 min ------ 6 shots 

90 min ------ ? shots 

=> 90 x (6/12) = 45 

Therefore, total shots fired in 90 minutes = 45 + 1 = 46 shots.

The given series follows the rule,
+(11x1), +(11x3), +(11x5), +(11x7), +(11x9),....

So starting from 7, 7 + 11 = 18, 18 + 33 = 51, 51 + 55 = 106, ...
So wrong number is 40 which is to be 51.