CAT Questions

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Let the efficiencies of filling pipes is 4p and 5p respectively.

Efficiency of pipe which empty the tank = 2/3 x 9p/2 = 3p

Total work = 3p x 36 = 108p

Time to fill the tank by both the pipes = 108p/9p = 12 min.

From the assumption and trial and error method,

last three digits sum must leave the same digit as the answer. It is possible only if the answer must be units digit number leaving tens digit as carry.

And the possible 3rd digit is 5. Since 5 + 5 + 5 = 15 

Now, 2nd step is  1 + x + x + x = 5

=> 3x = 4

It is possible with x = 8. 8 + 8 + 8 + 1 = 25 leaving 2 as carry. 

Now, 3rd step is 2 + x + x + x = 5 => x = 1

Hence, the three dgits are 1, 8, 5.

185 + 185 + 185 = 555. 

Given Circumference of a circular base of a cylinder = 44 cm

We know that Circumference of a circle = $$\begin{gathered} 2πr = 44 \\ ⇒r = 22π \end{gathered}$$

Now given the height of a cylinder h = 15 cm

Volume of a cylinder V = πr2h = π22π215 = 22 x 22 x 153.14 = 2311 cm3.

There are 600 Kabaddi players
4% wear knee band on one leg
Remaining players = 600 x 0.96 = 576
Of the remaining, 25% wear knee bands on both leg
and Of the remaining, 75% do not wear knee bands .
So players not wearing knee bands = 0.75 x 576 = 576 x 3/4 = 144 x 3 = 432.

Total age seven persons = (26 x 7)years
Total age of the first three persons and the last three persons are (19 x 3) years and (32 x 3) years respectively.
Age of the person sitting in the middle of the row = 26 x 7 - 19 x 3 - 32 x 3 = 182 - 57 - 96 = 29 years.

The total angle traced by the hour hand is the angle traced in 7 hours and 10 minutes.
We know that the angle traced by the hour hand in one hour is 30º and in one minute is 1/2º.
Therefore, (30º x 7) + (10 x 1/2º) = 215º is the angle traced by the hour hand.

DNA is a double-stranded molecule twisted into a helix. The shape of DNA is a double helix, which is like a twisted ladder. The sides of the ladder are made of alternating sugar and phosphate molecules. Deoxyribose, which is a pentose, and a phosphate group are the two molecules together form the two sides of the DNA. The rungs of the ladder are pairs of 4 types of nitrogen bases.