Question 575610
i dont know if its just me but im pretty sure we are missing some information
how many girls are in the class
how many students are in the class
how many boys in the class

it sounds like theres only 3 girls in the class but out of some other number. unless the class is only made up of the 3 girls and in that case theres no possibility for all 3 to pass if only 70% passed.