The sum of two numbers is 25 and their difference is 13. Find their product. Answers
A) 104 B) 108 C) 114 D) 325 E) None
Sol.   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= 
<gadget id="calculator">625 - 169</gadget>
<output>456</output>
456   ⇒ xy= 114.   Answer 114
<result>C</result>
The sum of two numbers is 25 and their difference is 13. Find their product.