Quantitative Aptitude - Arithmetic Ability Questions

Suppose the two liquids A and B are 7x litres and 5x litres respectivel Now, when 9 litres of mixture are taken out,

Now, when 9 liters of liquid B are added

To convert a fraction into decimal, just take the number on top which we called the numerator and divide it by the number at the bottom which we called the denominator.

2/3

How it comes :

$2÷3=0$ bring down the decimal point.

$20÷3=6$ and carry the remainder $2$ to make $20$

$20÷3=6$ and carry the remainder $2$ to make $20$

$20÷3=6$ and carry the remainder $2$ to make $20$

etc...

This gives the recurring decimal 0.6666...

If we round off to two decimals , then it becomes 0.67.

Hence, decimal fraction of 2/3 = 0.67.

Number of ways of selecting (3 consonants out of 7) and (2 vowels out of 4) =( C37×C24 ) = 210.

Number of groups, each having 3 consonants and 2 vowels =210

Each group contains 5 letters.

Number of ways of arranging 5 letters among themselves = 5! = 120. 

Required number of words = (210 x 120) = 25200.

5% of 40,000  = 5100 × 40,000 = 5 × 400 = 2,000  

Hence, 5% of 40,000 = 2,000.

Let the required number be 'p'

We know, sum of angles in a triangle are 180 deg

According to given data,

p - p/7 = 180

7p - p = 180 x 7

=> 6p = 1260

=> p = 1260/6 = 210

Let the required two numbers be a, b

From the given data,

2a + 3b = 36 .....(1)

3a + 2b = 39 .....(2)

Now, by solving 1 and 2 eqnts, we get

5a = 45

a = 9 ....(3)

Put (3) in (1), we get

2(9) + 3b = 36

=> 18 + 3b = 36

3b = 36 - 18

=> b = 18/3 = 6

Required, difference between the numbers = a + b = 9 + 6 = 15.

Ans. 
Distance covered by 1st train in 4 hours = 80*4 = 320 km
Relative speed of 2nd train = 120-80 = 40 km
It will overtake another train in 320/40 = 8 hours
Distance between overtake point and station A = 8*120 = 960 km