Nine pieces of 8 in. ✕ 12 in. duct that is 2 2 3 ft in length is needed for a building. What is the total length (in ft) needed?

This question is incomplete, the complete question is;

Nine pieces of 8-in. × 12-in. duct that is 2 ft in length is needed for a building. What is the total length (in ft) needed?

the total length needed is 24 ft

Step-by-step explanation:  

Given the data in the question;

the length of one piece of 8-in. × 12-in. duct is 2 ft

Now to find the total length for nine pieces of the duct;

we simple multiply 2 ft  by nine

so

Total length = 9 × 2  

we convert the mixed fraction to improper fraction

2  = 8/3

so

Total length = 9 × (8/3) ft

Total length = 24 ft

Therefore, the total length needed is 24 ft

it is a. 4.2 because 7.6-3.4 gets the remaining length of 4.2. i might be wrong but i am pretty sure this is the answer.