GATE Questions

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4 x 27 x 3125 = 22 × 33 × 55 ;

8 x 9 x 25 x 7 = 23 × 32 × 52 × 7

16 x 81 x 5 x 11 x 49 = 24 × 34 × 5 × 11 × 72

H.C.F = 22 × 32 × 5 = 180.

PWC refers to Personal Water Crafts.

To control steering on a PWC, the most needed requirement is to have power in which will allows the one using it to control the engine for it to stop or for it to move. Without power, the person using it could be out of balance or fail to start the engine. This is the basic requirement because even though it is shut off or the engine is off, the PWC is still on and it could still move without proper knowledge of the engine.

Let the number of students in classes A, B and C be P, Q and R respectively.
Then, total score of A = 83P, total score of B = 76Q, total score of C = 85R.
Also given that,
(83P + 76Q) / (P + Q) = 79
=>4P = 3Q.
(76Q + 85R)/(Q + R) = 81
=>4R = 5Q,
=>Q = 4P/3 and R = 5P/3
Therefore, average score of A, B, C = ( 83P + 76Q + 85R ) / (P + Q + R) = 978/12 = 81.5

Arun : Varun : Akhil = (20000 x 24) : (15000 x 24) : (20000 x 18) = 4:3:3

B's share = 25000 x 3/10 = Rs. 7500.

100C10 + 90C20 + 70C30 + 40C40 = 100!10!x20!x30!x40!

Let p = Rs. 100.

Then, S.I is Rs. 50 and time = 5 years. 

∴ R = 100×50100×5= 10% p.a.

Now, p = Rs. 12,000 , T = 3 years and R = 10% p.a.

C.I. = Rs. 12000×1+101003-1= Rs. 3972

Sony and her brother's age sum is 31
Let Sony's mother's age be 'x'.
Now the conditions given for both of their ages related to their mom is
1/5(x-15) + 3/5(x-10) = 31
x-15 + 3x-30 = 155
4x-45 = 155
4x = 200
x = 50
So, Mother's age = 50.

Cross verification : 15 years ago age = 35 => Sony age = 7
10 years ago age = 40 => bro age = 24

Sum = 24 + 7 = 31.

Let the principle be Rs. P
As the amount double itself the interest is Rs. P too
So P = P x r x 15/100
=> r = 100/15 = 20/3 % = 6.66 %.