Quantitative Aptitude - Arithmetic Ability Questions

Number of spades in a standard deck of cards=13
Number of aces in a standard deck of cards=4
And,one of the aces is a spade.
So, 13 + 4 - 1 = 16 spades or aces to choose from.
Therfore,probabiltiy of getting a spade or an ace=16/52=4/13

Capacity of the tank =(12 x 13.5) liters =162 liters.

Capacity of each bucket =9 liters

Number of buckets needed = 162/9 =18.

Let the time taken by train be 't' hrs.

Then,

40t = 35t + 1560

40t = 35t + 35/4

t = 7/4 hrs

Therefore, Required length of the total journey d = s x t

= 40 x 7/4

= 70 kms.

It is the same as a person with 20 years more age  replaces an existing person of the group ( or village)

Since the total age of the village having n persons, is being increased by 20 years and the average age of village is being increased by 1 year, hence there are total 20 people in the village.

Alternatively :  ( n x 42 ) + 20 = ( n x 43 )

                          => n=20

S.I. on Rs.800 for 1 year

=Rs[840 - 800]

= Rs.40

Rate

=(100x40/800x1)%

= 5%

I      II     III

65   58   100

65 -------- 7
100 ------ ?  => 10.769%

By trial and error method, we get
2880/3 = 960 is not a perfect square
2880/4 = 720 is not a perfect square
2880/5 = 576 which is perfect square of 24
Hence, 5 is the least number by which 2880 must be divided in order to make it into a perfect square.

Copper in 4 kg = 4/5 kg          and      Zinc in 4 kg = 4 x (4/5) kg

Copper in 5 kg = 5/6 kg          and      Zinc in 5 kg = 5 x (5/6) kg

Therefore, Copper in mixture = 45+56=4930 kg

and  Zinc in the mixture = 165+256=22130kg

Therefore the required ratio = 49 : 221