The maximum length of a certain type of fish is 60 centimeters. The difference between the maximum length and the length at age years is given by $D = 57 \times 0.86 ^ { t }$ centimeters. Write a formula
That gives the length L , in centimeters, of the fish at age years.
A) $L = 60 + 57 \times 0.86 ^ { t }$
B) $L = 60 - 57 \times 0.86 ^ { t}$
C) $L = 60 \times 57 \times 0.86 ^ { t }$
D) $L = 57 \times 0.86 ^ { t} - 60$

Question

The maximum length of a certain type of fish is 60 centimeters. The difference between the maximum length and the length at age  years is given by $D = 57 \times 0.86 ^ { t }$ centimeters. Write a formula
That gives the length L , in centimeters, of the fish at age  years. 
A) $L = 60 + 57 \times 0.86 ^ { t }$ 
B) $L = 60 - 57 \times 0.86 ^ { t}$ 
C) $L = 60 \times 57 \times 0.86 ^ { t }$ 
D) $L = 57 \times 0.86 ^ { t} - 60$

Quizplus · Accepted Answer

The question asks for the formula giving the length of the fish at age 11 years. The maximum length of the fish is 60 centimeters, which means that the length at age 11 years must be less than 60 centimeters. Therefore, the difference between the maximum length and the length at age 11 years given by $D = 57 \times 0.86 ^ { t }$ must be subtracted from the maximum length to get the length of the fish at age 11 years. Thus, the formula is: 
$$L = 60 - 57 \times 0.86 ^ { t}$$

The Maximum Length of a Certain Type of Fish Is D=57×0.86tD = 57 \times 0.86 ^ { t }D=57×0.86t

The Maximum Length of a Certain Type of Fish Is $D = 57 \times 0.86 ^ { t }$