Airplanes are sometimes used to fight fires . A certain airplane can deliver 3.9 * 10^4 liters of water in one trip . How much water can this airplane reliever in 7 trips ? write the answer in scientific notation .

The question is kind of confusing. if it's asking how many variations of answers can you give. then do 4^5 for your answer.this would be something like the first question could be a and the 2nd c or first b next c etc. if you can, ask the teacher for a better confirmation of what it's asking. if i'm assuming correctly what it's asking, it's 625 different variations.