A fish was caught whose tail weighed 9lb. It's head weighed as much as it's tail plus half it's body. It's body weighed as much as it's head and tail. What did the fish weigh?

Question

anonymous · Answer

Let t= weight of tail
Let b=weight of body
Let h= eight of head
Given: t= 9
h=t+b/2 (b over 2) 
b=h+t
By substitution: h= 9+b/2
1) 2h=18+b              subtracted the b to isolate the 18
2h-b=18               divided the 2 to get 9
b=h+9
2) h-b=-9                 subtracted the b to isolate the -9
Then subtract 2h-b=18 from -h+b=9
h=27
Since b = h+9 
b=27+9 
b=36
The fish weighs 9+27+36=72