John's cow weighs 400 pounds.  It increased its weight to 1.5 times its starting weight.  He is able to sell the cow for $3 per pound.  How much more is it worth after gaining the weight?
The cow initially weighs 400*1.5=<T>multiply(400, 1.5)=600.0 pounds
So it gained 600 - 400 = <T>subtract(600, 400)=200 pounds
So its value increased by 200*$3 = $<T>multiply(200, 3)=600
