Granny has taken up deep-sea fishing! Last week, she caught a fish so big that she had to cut it into 3 pieces (head, body and tail) in order to weigh it. The tail weighed 9kg and the head weighed the same as the tail plus one third of the body. The body weighed as much as the head and tail together. How much did the whole fish weigh?

54kg

Step-by-step explanation:

Body weight = B

Tail weight = T

Head weight = H

Total weight = F

Use equation = B + T + H = F

We are told that T = 9kg, H = T + (1/3) x B, B = H + T

We have 3 equations and 3 unknowns, solve the system of equations to find W.  

B = H + 9

H = 9 + 1/3 x (H+9)=9+H/3+3 --> 2/3 x H = 12  --> H = 18

B = 18 + 9 = 27

F = 18 + 27 + 9 = 54kg

step-by-step explanation:

mean or average is 40.6