In a primary school, 10% of students are below 11 years of age. The number of students above 11 years of age is 3/4 of the number of students of 11 years of age which is 36. What is the total number of students in the school?  Choose the correct answer:
A) 72 B) 80 C) 70 D) 150 E) None of these
Explanation :   Let the number of students be x.   Then, Number of students above 11 years of age = (100 - 10)= 
<gadget id="calculator">(100 - 10)</gadget>
<output>90</output>
90% of x.   90% of x= 36 + 3/4 of 36   90x/100 = 63   x = 70.   Answer : 70
<result>C</result>
In a primary school, 10% of students are below 11 years of age. The number of students above 11 years of age is 3/4 of the number of students of 11 years of age which is 36. What is the total number of students in the school?