Class 10R sat a test, the mean mark for the class was 70%, there are 30 students in 10R, 20 are boys the mean mark for boys was 62% what is mean mark for girls

Determine whether the quadrilateral below is a parallelogram. justify/explain your answer (this means back it up! give specific information that supports your decision. writing just "yes" or "no" will result in no credit.)

Ben is three times as old as samantha, who is two years older than half of michel's age. if michel is 12. how old is ben?

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.