In alphabet series, some alphabets are missing which are given in that order as one of the alternatives below it. Choose the correct alternative.

adb _ ac _ da _ cddcb _ dbc _ cbda

The series is adbc acbd abcd dcba dbca cbda.

Thus, the letters equidistant from the beginning and the end of series are the same.

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For a motor boat that cover A certain distance downstream in 2 hours and return 3 hours what would be its speed in still water if the speed of stream is equal 6 km per hour?

Speed of boat in still water=y[(t1+t2)/(t1_t2)]km/hr

Speed of boat in still water=x=6[(3+2)/(3-2)]=30 km/hr

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The ratio of two brothers John and Harry is 4 / 5 . However if the age of John before 10 years and that of Harry after 10 years than the original ratio is reversed. What is the age of Harry?

let's John age =a and Harry age = b

Given that

a/ b =5 / 4

4 a=5 b

4a- 5b =0..... equation 1

and also given that

a - 10 / b + 10 =4 / 5

a5 - 50= 4b+40

5 a- 4b= 90 .......equation 2

By solving both equation

so, Harry is 40 years old.

A family consists of six members P, Q, R, X, Y and Z. Q is the son of R but R is not mother of Q. P and R are a married couple. Y is the brother of R. X is the daughter of P. Z is the brother of P. Who is the brother-in-law of R?

Q is the son of R but R is not the mother. So, R is the father of Q. P is married to R. So, P is the wife of R and the mother of Q. X is the daughter of P and hence of R and so she is the sister of Q. Y is the brother of R and Z is the brother of P. R is the husband of P and Z is the brother of P. So, Z is the brother-in-law of R..

Which one of the following is a prime number ?

551 > 22

All prime numbers less than 24 are : 2, 3, 5, 7, 11, 13, 17, 19, 23.

119 is divisible by 7; 187 is divisible by 11; 247 is divisible by 13 and 551 is divisible by 19.

So, none of the given numbers is prime.

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