Solve 10¹⁵/10⁵ Simplified and what law did you use

9/10 divide by -3/15 as a mixed number

The floor of a building consists of 3000 tiles which are rhombus shaped and each of it's diagonals are 45 cm and 30 cm in length. find the total cost of polishing the floor, if the cost per m² is rs. 4.

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?