Find the number which multiplied by 15 is increased by 56 ?

Correct Answer: 3 hrs

Explanation:

Let t be the usual time. If the usual rate is 1 unit, then the unusual rate is 6/7.
Balance by the distance,
1 x t = (6/7)(t + 30)
7t = 6(t + 30)
we get t as,
t = 180 minutes = 3 hrs.

Correct Answer: 6 painters

Explanation:

Two painters can complete two rooms in two hours.So 18 rooms can be painted in 6 hrs by 6 painters

Correct Answer: 253

Explanation:

Let the middle digit be x.

Then, 2x = 10 or x = 5. So, the number is either 253 or 352

Since the number increases on reversing the digits, so the hundred's digit is smaller than the unit's digit.

Hence, required number = 253.

Correct Answer: 9944

Explanation:

To find the largest 4 digit number exactly divisible by 88,

We should divide the largest possible 4 digit number by 88, and if we get any remainder than subtract it from that largest number.

The largest possible 4 digit number is 9999

Now,

 

88) 9999 (113
      88
  _______
      119
        88
  _______
        319
        264
  _______
          55
  _______

 

Therefore, the largest 4 digit number exactly divisible by 88 is given by

9999 - 55 = 9944.

Correct Answer: 22

Explanation:

Let each literature text book cost be Rs. X

Then, cost of mathematics text book = Rs. (X + 2)

ATQ,

5X = 38 + 3(X + 2)

5X = 38 + 3X + 6

2X = 44

X = 22.

 

Therefore, cost of each literature text book = Rs. X = Rs. 22.

And that of masthematics = X + 2 = Rs. 24.

Correct Answer: 0.5

Explanation:

In mathematics, a geometric progression, also known as a geometric sequence, is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio.

 

Herein the given sequence, 4, 2, 1, 0.5, 0.25, 0.125,...

Common Ratio r = 2/4 = 1/2 = 0.5/1 = 0.25/0.5 = 0.125/0.25 == 0.5.

Correct Answer: 8

Explanation:

Let the number be v. Then, 3 (2x + 9) = 75.

 2x + 9 = 25

=> 2x = 16

=> x = 8

Correct Answer: 2/3

Explanation:

Let the fraction be x/y. Then, x /(y+1) = 1/2

=> 2x - y = 1  ..........(i)and 

(x + 1) / y = 1  => x - y =  1 .......(ii)

 Solving (i) and (ii), we get :  x  = 2, y = 3. Hence, the required fraction is 2/3..

Correct Answer: data inadequate

Explanation:

Let the ten's digit be x and unit's digit be y. Then, (10x + y) - (x + y) = 9 or x = 1.

From this data we cannot find  y, the unit's digit. So the data is inadequate..

Correct Answer: 5

Explanation:

This is a quadratic equation. To find n we multiply the last terms in each bracket together (2 times -5) = -10

To find ?a? we multiply the first terms in each bracket together (3x times 2x) = 6x2, So a = 6.

Thus a - n = 16

To find k we multiply the first term in the first bracket by the second term in the second bracket and add the result to the product of the second term in the first bracket and the first term in the second. (-15x + 4x) = -11x. So k = -11

16 - 11 = 5