General Questions

Answer: Option C

Explanation:

Let the number of students in rooms A and B be x and y respectively.

Then, x - 10 = y + 10      x - y = 20 .... (i)

     and x + 20 = 2(y - 20)      x - 2y = -60 .... (ii)

Solving (i) and (ii) we get: x = 100 , y = 80.

The required answer A = 100.

Answer: Option

Explanation:

Let the price of a saree and a shirt be ₹x and ₹ y respectively.

Then, 2x + 4y = 1600 .... (i)

    and x + 6y = 1600 .... (ii)

Divide equation (i) by 2, we get the below equation.

=> x + 2y = 800. --- (iii)

Now subtract (iii) from (ii)

 x +  6y = 1600 (-)
 x +  2y =  800  
----------------
      4y =  800
----------------

Therefore, y = 200.

Now apply value of y in (iii)

=> x + 2 x 200 = 800

=> x + 400 = 800

Therefore x = 400

Solving (i) and (ii) we get x = 400, y = 200.

Cost of 12 shirts = ₹ (12 x 200) = ₹ 2400.

Answer: Option D

Explanation:

Let number of notes of each denomination be x.

Then x + 5x + 10x = 480

16x = 480

x = 30.

Hence, total number of notes = 3x = 90.

Answer: Option A

Explanation:

2ab = (a² + b²) - (a - b)²

   = 29 - 9 = 20

   ab = 10.

Answer: Option D

Explanation:

Let the cost of a chair and that of a table be ₹ x and Rs. y respectively.

15x + 2y = 4000

15x + 2 x	5	x = 4000
	2

20x = 4000

x = 200.

So, y =		5	x 200		= 500.
		2

Hence, the cost of 12 chairs and 3 tables = 12x + 3y

    = ₹ (2400 + 1500)

    =₹ 3900.

Answer: Option C

Explanation:

Suppose their paths cross after x minutes.

Then, 11 + 57x = 51 - 63x      120x = 40

Number of floors covered by David in (1/3) min.

=		1	x 57		= 19.
		3

So, their paths cross at (11 +19) i.e., 30^th floor.

Answer: Option B

Explanation:

Suppose the man works overtime for x hours.

Now, working hours in 4 weeks = (5 x 8 x 4) = 160.

160 x 2.40 + x x 3.20 = 432

3.20x = 432 - 384 = 48

x = 15.

Hence, total hours of work = (160 + 15) = 175.

Answer: Option D

Explanation:

Let the number of hens be x and the number of cows be y.

Then, x + y = 48 .... (i)

  and 2x + 4y = 140      x + 2y = 70 .... (ii)

Solving (i) and (ii) we get: x = 26, y = 22.

The required answer = 26.

Answer: Option C

Explanation:

Let total number of children be x.

Then, x x	1	x =	x	x 16    x = 64.
	8		2

Number of notebooks :

=	1	x2 =		1	x 64 x 64		= 512.
	8			8

Answer: Option B

Explanation:

   = 4 (where a = 469, b = 174.)