Correct Answer: 17

Explanation:

The pattern is  3 2 + 4 2 = 5 2,   5 2 + 12 2 = 13 2,  7 2 + 24 2 = 25 2 

The next number =  8 2 + 15 2 = 17 2

 i.e. 17

Correct Answer: 2

Explanation:

Since 653xy is divisible by 5 as well as 2, so y = 0.
Now, 653x0 must be divisible by 8.
So, 3x0 must be divisible by 8. This happens when x = 2
x + y = (2 + 0) = 2.

Correct Answer: 32

Explanation:

Probability of left handed = 4/5
total student = 40
total left handed = 40 x(4/5)
= 32

Correct Answer: 788

Explanation:

(kx22)/100 = 340 - 166.64 = 173.36
k = (173.36 x 100)/22
k = 788

Correct Answer: 31

Explanation:

Let the three consecutive odd numbers be x, x+2, x+4

Then,

x + x + 2 + x + 4 = 93

=> 3x + 6 = 93

=> 3x = 87

=> x = 29 => 29, 31, 33 are three consecutive odd numbers.

 

Therefore, the middle number is 31.

Correct Answer: 12

Explanation:

we can do this by trial and error method.

Putting x = 2,we get 2²(2² - 1) = 12.
checking with other integers, the above equation always gives a value which is a multiple of 12,
So, x²(x² - 1) is always divisible by 12.

Correct Answer: 8

Explanation:

9321 = 3 x 13 x 239 = 31 x 13 1 x 239 1 ; add one to all the powers ie.,

(1+1) x (1+1) x (1+1)= 8 ;

we get eight factors.

Correct Answer: 1

Explanation:

The mutiplicative inverse of a number is nothing but a reciprocal of a number.

Now, the product of a number and its multiplicative inverse is always equal to 1.

 

For example :

Let the number be 15

Multiplicative inverse of 15 = 1/15

The product of a number and its multiplicative inverse is = 15 x 1/15 = 1.

Correct Answer: 961 x 961

Explanation:

We know that  a m × a n = a m + n 

? 31 31 - 27 =  31 4 = 961 x 961.

Correct Answer: 0

Explanation:

15 23 + 23 23 = 19 - 4 23 + 19 + 4 23  

 The remainder on dividing by 19 will be  - 4 23 + 4 23= 0.