There are 120 student in class in which 20 of them are girls and rest boys.if the average marks in math of boys is 65% and that of girls is 80%. find the average marks of the class
To find the average marks of the class, we need to calculate the total marks of all the students and divide it by the total number of students.
First, let's calculate the total number of boys in the class. We know that there are 120 students in total and 20 of them are girls, so the number of boys will be 120 - 20 = 100.
Now, let's calculate the total marks obtained by the boys. We know that the average marks of boys is 65%. To find the total marks, we need to calculate 65% of the total possible marks. Let's assume the total possible marks are 100 (you can adjust this based on the actual total marks for math in your class). Therefore, the total marks obtained by boys will be (65/100) * 100 * 100 = 65 * 100 = 6500.
Next, let's calculate the total marks obtained by the girls. We know that the average marks of girls is 80%. Following the same logic, the total marks obtained by girls would be (80/100) * 100 * 20 = 80 * 20 = 1600.
To find the total marks of the class, we need to sum up the marks of boys and girls, which is 6500 + 1600 = 8100.
Finally, we divide the total marks by the total number of students to find the average marks of the class. Therefore, the average marks of the class would be 8100/120 = 67.5%.
Hence, the average marks of the class is 67.5%.