Question

Class 10R sat a test ,The mean mark for the class was 70% ,there are 30 students in class 10R,20 of whom are boys.The mean mark for boys in the test was 62% .
Work out the mean mark for girls

Answer 1

Answer:

The mean marks of the girls is 86%

Step-by-step explanation:

number of students in the class 30

number boys 20

number girls= 30-20=10

mean mark of the boys 62

mean marks of the class 70

so mean marks of the girls is

$20 \times 62 + 10x = 30 \times 70 \\ 1240 + 10x = 2100 \\ 10x = 2100 - 1240 \\ 10x = 860 \\ x = \frac{860}{10} \\ x = 86$

the mean marks of the girls is 86%

Answer 2

Answer:

86%

Step-by-step explanation: