Aptitude and Reasoning Questions

Probability of getting 6 at the top once =1/6

Probability of getting 6 at the top three times =1/6 x 1/6 x 1/6 =216

Probability of no getting 6 at he top any time = 1 - 1/216 = 215/216

Number of non - negative integral solutions =n+r-1 Cr-1 = C223 = 253 

Letters in the word                          Letters in the alphabet

SEQ                                                      SRQ

QUEN                                                  QPON

SEQUEN                                               SRQPO

ENTIA                                                  EDCBA 

Let Ishika and her daughter present ages be p and q

 From the given data, 

p = 4/3(p - 9)

 => p = 36 years 

Hence, Ishika's present age = 36 years and

Her daughter's present age = 1/6 x 36 = 6 years 

Now, required her daughter’s age three years ago = 6 - 3 = 3 years.

Second is obtained from the first.

We can select atleast one item from 6 different items = 26-1  

Similarly we can select atleast one item from other set of 6 different items in 26-1 ways. 

Required number of ways = (26-1)26-1 = 26-12 = 3969

Let the speed of the faster train be 'S' kmph

Then speed of the slower train will be '(S-5)' kmph

Time taken by faster train = 350/S hrs

Time taken by slower train = 350/(S-5) hrs

 350s-5 - 350s = 2 hrs 20 min = 213 = 73

=> S = 30 km/hr.

Let the ratio of initial quantity of oils be 'x' => 4x, 5x & 8x.
Let k be the quantity of third variety of oil in the final mixture.
Let the ratio of initial quantity of oils be 'y'
From given details,
4x + 5 = 5y ..... (1)
5x + 10 = 7y .....(2)
8x + k = 9y ......(3)

By solving (1) & (2), we get
x = 5 & y = 5

From (3) => k = 5

Therefore, quantity of third variety of oil was 9y = 9(5) = 45kg.