The grade point average of one third of the classroom is 45; the grade point average of the rest is 60. What is the grade point average of the whole class?  Choose the correct answer:
A) 54  B) 55  C) 60  D) 65  E) 70
Let n=total students in class   total points for 1/3 class=45n/3=15n   total points for 2/3 class45 /3= 
<gadget id="calculator">45 /3</gadget>
<output>15</output>
15n   total points for 2/3 class=60*2n/3=40n   total points for whole class60*2 /3= 
<gadget id="calculator">60*2 /3</gadget>
<output>40</output>
40n   total points for whole class=15n+40n=55n   63n total class points/n total students15 +40= 
<gadget id="calculator">15 +40</gadget>
<output>55</output>
55n   63n total class points/n total students=55 grade point average for total class   Answer : 55
<result>B</result>
The grade point average of one third of the classroom is 45; the grade point average of the rest is 60. What is the grade point average of the whole class?