A submarine on the surface of the ocean descended at a rate of 7 feet per second for 2 minutes. Then it ascended at a rate of 4 feet per second for 3 minutes, Finally, it descended at a rate of 9 feet per second for 5 minutes. What was the final elevation of the submarine?

I believe the answer is 2,820 feet.

Step-by-step explanation:

First, you would need to multiply 60 by however many minutes to see how many seconds there are.

Second, multiply the number of feet by the seconds you found from the first step.

Lastly, add together the two descending part. Then subtract it from the ascending part.

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this

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