The average marks of a class of 30 students is 30 and that of another class of 50 students is 60. Find the average marks of all the students? Options:
A) 52.5
B) 52.9
C) 52.1
D) 48.75
E) 42.5
Sum of the marks for the class of 30 students = 30 * 30= 
<gadget id="calculator">30 * 30</gadget>
<output>900</output>
900   Sum of the marks for the class of 50 students= 50 * 60= 
<gadget id="calculator">50 * 60</gadget>
<output>3_000</output>
3000   Sum of the marks for the class of 80 students=   900 + 3000= 
<gadget id="calculator">900 + 3000</gadget>
<output>3_900</output>
3900   Average marks of all the students= 3900/80= 
<gadget id="calculator">3900/80</gadget>
<output>195/4 = around 48.75</output>
48.75   Answer:48.75
<result>D</result>
The average marks of a class of 30 students is 30 and that of another class of 50 students is 60. Find the average marks of all the students?