James hires a seamstress to fix all his shirts and pants.  He has 10 shirts and 12 pairs of pants.  It takes 1.5 hours to fix a shirt and twice as long for pants.  The tailor charges $30 per hour.  How much does it cost?
It takes 10*1.5=<T>multiply(10, 1.5)=15.0 hours to fix his shirts
It takes 1.5*2=<T>multiply(1.5, 2)=3.0 hours per pair of pants
So it takes 3*12=<T>multiply(3, 12)=36 hours for the pants
That means in total it takes 15+36=<T>add(15, 36)=51 hours
So it cost 51*30=$<T>multiply(51, 30)=1530 to fix everything
