A library has 7 rectangular tables and the remaining tables will be square tables. A rectangular table seats 10 pupils while a square table seats 4 pupils. How many square tables are needed so that 90 pupils can read at the same time?
The rectangular tables seat 7*10=<T>multiply(7, 10)=70 pupils.
The square tables will seat 90-70=<T>subtract(90, 70)=20 pupils.
The library needs 20/4=<T>divide(20, 4)=5.0 square tables.
