If the sum and difference of two numbers are 5 and 10 respectively, then the difference of their square is:	Select:  A) 50  B) 28  C) 160  D) 180  E) 18
Let the numbers be x and y.   Then, x + y = 5 and x - y = 10   x2 - y2 = (x + y)(x - y) = 5 * 10= 
<gadget id="calculator">5 * 10</gadget>
<output>50</output>
50.   50NSWER:50
<result>A</result>
If the sum and difference of two numbers are 5 and 10 respectively, then the difference of their square is: