Quantitative Aptitude - Arithmetic Ability Questions

Any number which can be expressed as a fraction of two integers like P & Q as P/Q where Q is not equal to zero.

Every integer is a rational number since Q can be 1.

Hence, in the given options, 4 can be expressed as a simple fraction as 4/1. And all other options cannot be expressed as fractions.

Hence, 4 is a rational number in the given options.

Working efficiency of both typist together = 100/6 = 16.66%

Let the efficiency of first typist be x and second typist be (16.66 –x)

First typist for 4 minute + second tyoistfor 6 minute = 80% work

⇒4x + (16.66 –x) X 6 = 80%

⇒4x + 100% -6x = 80%,

⇒x = 10%

First typist typed 10% per minute, second typst typed (16.66 –10) = 6.66% per minute

Slowest is second typist complete whole job in 100/6.66 = 15.01 = 15 minute

Two digit numbers: The two digits can be 2 and 9: Two possibilities 29 and 92.

Three-digit numbers: The three digits can be 1, 2 and 9 => 3! Or 6 possibilities.

We cannot have three digits as (3, 3, 2) as the digits have to be distinct.

We cannot have numbers with 4 digits or more without repeating the digits.

So, there are totally 8 numbers.

S=R[(1+i)^n-1)/i]

Total weight of 50 boys = 45 X 50 = 2250

Average weight of 49 boys = 44.9

Total weight of 49 boys = 44.9 X 49 = 2200.1

Weight of boy who left the class=2250–2200.1=49.9

Let present age of Pranay = 15p

That of Sai = 17p

ATQ,

15p + 6/17p + 6 = 9/10

=> 150p + 60 = 153p + 54

=> p = 2

Therefore, Age of Pranay after 6 yrs = 15 x 2 + 6 = 36 years.