Quantitative Aptitude - Arithmetic Ability Questions

Let the length of the 1st train = L mts

Speed of 1st train = 48 kmph

Now the length of the 2nd train = L/2 mts

Speed of 2nd train = 42 kmph

Let the length of the bridge = D mts

Distance = L + L/2 = 3L/2

Relative speed = 48 + 42 = 90 kmph = 90 x 5/18 = 25 m/s(opposite)

Time = 12 sec

=> 3L/2x25 = 12

=> L = 200 mts

Now it covers the bridge in 45 sec

=> distance = D + 200

Time = 45 sec

Speed = 48 x5/18 = 40/3 m/s

=> D + 200/(40/3) = 45

=> D = 600 - 200 = 400 mts

Hence, the length of the bridge = 400 mts.

Let the sum(principal) received by A and B are x and y.

(1+r) =  =

Then,  =

Hence, the ratio in which the sum is divided =121:100

Let the present age of Raj and Rajitha be 4x and 9x.
Then, according to question,
9x = 2(9x-12)-3 => 9x = 27 => x = 3
Raj's present age = 4x = 12yrs,
After 5 years Raj's age will be 12 + 5 = 17 yrs.

As in this problem , buying any fruit is different case , as buying apple is independent from buying banana. so ADDITION rule will be used.

C19+C18+C16 = 23 will be answer.

1523+2323=19-423+19+423  

 The remainder on dividing by 19 will be -423+423= 0.

Let the rquired number be 'P'

According to the question,

$$\begin{gathered} 100 x P100 = 20 \\ => P = 20 x 100100 = 20 \end{gathered}$$

Hence, 100 percent of the number 20 is 20.

Now, you can also try for

20 percent of what number is 100

$$\begin{gathered} 20 x P100 = 100 \\ => P = 100 x 10020 = 500 \\ => P = 500 \end{gathered}$$

Hence, 20 percent of the number 500 is 100.

  LCD is nothing but Lowest or Least Common Denominator

Here LCD of 12 and 18 means LCD of two fractions with denominators 12 and 18 respectively.

Therefore, LCM of 12 & 18 = 6 x 3 x 2 = 36 

•  How to calculate LCD ::

The lowest common denominator or least common denominator (LCD) is the least common multiple (LCM) of the denominators of a set of fractions.