a2zinterviews

19.	(7.5 x 7.5 + 37.5 + 2.5 x 2.5) is equal to
	A.  30
	B.  70
	C.  100
	D.  120

Solution

Given expression = (7.5 x 7.5 + 2 x 7.5 x 2.5 + 2.5 x 2.5) a2 + 2ab + b2 = (a + b)2 ‹=›(7.5 + 2.5)2 ‹=›102 = 100.

20.	0.002 x 0.5 = ?
	A.  0.00001
	B.  0.001
	C.  0.01
	D.  0.1

Solution

2 x 5 = 10. Sum of decimal places = 4. ∴ 0.002 x 0.5 = 0.0010 = 0.001.

21.	3889 + 12.952 - ? = 3854.002
	A.  47.095
	B.  47.752
	C.  47.932
	D.  47.95

Solution

Let 3889 + 12.952 - x = 3854.002. Then, x = (3889+12.952)-3854.002 = 3901.952 - 3854.002 = 47.95.

22.	0.014 x 0.014 = ?
	A.  0.000196
	B.  0.00196
	C.  19.6
	D.  196

Solution

14 x 14 = 196. Sum of decimal places = 6. ∴ 0.014 x 0.014 = 0.000196.