The average marks of a class of 30 students is 40 and that of another class of 50 students is 60. Find the average marks of all the students? Choices:
A) 52.6	B) 52.4	C) 52.1	D) 52.5	E) 52.9
Sum of the marks for the class of 30 students = 30 * 40= 
<gadget id="calculator">30 * 40</gadget>
<output>1_200</output>
1200   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=   1200 + 3000= 
<gadget id="calculator">1200 + 3000</gadget>
<output>4_200</output>
4200   Average marks of all the students= 4200/80 = 52.5.Answer: 52.5
<result>D</result>
The average marks of a class of 30 students is 40 and that of another class of 50 students is 60. Find the average marks of all the students?