a2zinterviews

21.	Thrice the square of a natural number decreased by 4 times the number is equal to 50 more than the number. The number is
	A.  4
	B.  5
	C.  6
	D.  7

Solution

Let the number be x. Then, 3x2 - 4x = x + 50 ‹=› 3x2 - 5x - 50 = 0 ‹=› (3x + 10) (x - 5) = 0. ‹=› x = 5..

22.	A number is as much greater than 36 as is less than 86. Find the number.
	A.  41
	B.  51
	C.  61
	D.  81

Solution

Let the numbers be x. Then, x - 36 = 86 - x ‹=›2x = 86 + 36 = 122 ‹=›x = 61.

23.	A two digit number becomes five sixth of itself when its digits are reversed. The two digits differ by one. The numebr is
	A.  45
	B.  54
	C.  56
	D.  65

Solution

Since the number reduces on reversing the digit's, so ten's digit is greater than the unit's digit. Let the units digit be x. Then, ten's digit = (x + 1) Therefore, 10x + (x+1) = 5/6[10(x+1)+x] ‹=›66x + 6 = 55x + 50. ‹=›11x= 44. ‹=›x= 4.

24.	The difference between a number and its three fifth is 50. What is the number?
	A.  75
	B.  100
	C.  125
	D.  180

Solution

Let the number be x. Then, x - 3 / 5x = 50 ‹=› 2 / 5 x = 50 ‹=›x = (50 x 5 / 2) ‹=›125.

25.	The sum of three consecutive numbers is 87. The greatest among these three numbers is
	A.  26
	B.  28
	C.  29
	D.  30

Solution

Let the numbers be x, x+1 and x+2. Then, x + (x+1) + (x+2) = 87 ‹=›3x = 84 ‹=› x = 28. Therefore Greatest number = (x + 2) = 30.