Jhon's average (arithmetic mean) test score on 5 tests is 87. What must be the Jhon's score on a 6th test for the Jhon's average score on the 6 tests to be 85?
Choose one:	A) 65	B) 75	C) 85	D) 95	E) 105
(5*87+x)/6=85   x=(6*85)-(5*87)   x= 510 - 435= 
<gadget id="calculator">510 - 435</gadget>
<output>75</output>
75   Correct answer is 75
<result>B</result>
Jhon's average (arithmetic mean) test score on 5 tests is 87. What must be the Jhon's score on a 6th test for the Jhon's average score on the 6 tests to be 85?