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=<<400*1.5=600>>600 pounds
So it gained 600 - 400 = <<600-400=200>>200 pounds
So its value increased by 200*$3 = $<<200*3=600>>600
#### 600