a2zinterviews

16.	The sum of two numbers is 25 and their difference is 13. Find their product?
	A.  104
	B.  114
	C.  315
	D.  325

Solution

Let the numbers be x and y. Then, x+y = 25 and x-y = 13. 4xy = (x + y)2 - (x - y)2 ‹=› (25)2 - (13)2 ‹=› 625 - 169 = 456 ‹=› xy = 114.

17.	If the sum of two numbers is 22 and the sum of their squares is 404, then the product of the numbers is
	A.  40
	B.  44
	C.  80
	D.  88

Solution

Let the numbers be x and y. Then, (x+y) = 22 and x2+y2 = 404. Now, 2xy= (x+y)2 - (x2+y2) = (22)2 - 404 = 484 - 404 = 80 Therefore xy = 40.

18.	Three times the first of three consecutive odd integers is 3 more than twice the third. The third integer is
	A.  9
	B.  11
	C.  13
	D.  15

Solution

Let the three integers be x, x+2 and x+4. Then, 3x = 2(x+4)+3 ‹=›x= 11. Therefore, third integer x+4 = 15.

19.	A number is doubled and 9 is added. If the resultant is trebled, it becomes 75. What is that number?
	A.  3.5
	B.  6
	C.  8
	D.  None of these

Solution

Let the number be x. Then, 3(2x + 9) ‹=› 75 ‹=› 2x+9 = 25 ‹=› 2x= 16 x= 8.

20.	A number consists of 3 digits whose sum is 10. The middle digit is equal to the sum of the other two and the number will be inceased by 99 if its digits are reserved. The number is
	A.  145
	B.  253
	C.  370
	D.  352

Solution

Let the middle digit be x. Then, 2x= 4 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's the unit's digit. Hence the required number is 253.