Answer: The weight of blue marlin= 252 pounds
The weight of amber-jack = 21 pounds
Step-by-step explanation:
Let x be the weight of blue marlin and y be the weigh of amber-jack.
According to the give question , we have the following system of equations :

Substitute the value of x from equation (1) in (2), we get

Divide both sides by 13 , we get
y= 21
Put value of y in (1), we get

Hence, the weight of blue marlin= 252 pounds
The weight of amber-jack = 21 pounds