4students spent twelve dollars. what is the amount 10 students would spend?

Can someone check if i did this correct. it’s number 4 if you’re wondering.

There are 40 girls and 32 boys who want to participate in 6th grade intramurals. if each team must have the same number of girls and the same number of boys, what is the greatest number of teams that can participate in intramurals? how many girls and boys will be on each team?

Acertain drug is made from only two ingredients: compound a and compound b. there are 3 millimeters of compound a used for every 4 millimeters of compound b. if a chemist wants to make 693 milliliters of the drug, how many milliliters of compound a are needed?