If the sum and difference of two numbers are 15 and 10 respectively, then the difference of their square is:  Choose the correct choice:
A) 12
B) 150
C) 160
D) 180
E) 18
Let the numbers be x and y.   Then, x + y = 15 and x - y = 10   x2 - y2 = (x + y)(x - y) = 15 * 10= 
<gadget id="calculator">15 * 10</gadget>
<output>150</output>
150.   ANSWER:150
<result>B</result>
If the sum and difference of two numbers are 15 and 10 respectively, then the difference of their square is: