A notebook costs three times as much as a pen. If a pen costs $1.50, how much will Lyle pay for 4 notebooks?
A notebook costs $1.50 x 3 = $<T>multiply(1.5, 3)=4.5.
So Lyle will pay $4.50 x 4 = $<T>multiply(4, 4.5)=18.0 for the 4 notebooks.
