The elementary school has 19 fourth graders, 23 fifth graders, and 29 six graders. Fourth graders have 30 minutes of homework per night, fifth graders have 40 minutes of homework per night, and six graders have 60 minutes of homework per night. How many minutes per night does the average student with homework have?
Choices:
A) about 30 minutes
B) about 40 minutes
C) about 45 minutes
D) about 50 minutes
E) about 60 minutes
Explanation:   19 23 29   30 40 60   570 + 920 + 1740= 
<gadget id="calculator">570 + 920 + 1740</gadget>
<output>3_230</output>
3230/71= about 45 minutes   about 45 minutes
<result>C</result>
The elementary school has 19 fourth graders, 23 fifth graders, and 29 six graders. Fourth graders have 30 minutes of homework per night, fifth graders have 40 minutes of homework per night, and six graders have 60 minutes of homework per night. How many minutes per night does the average student with homework have?