At a concert $720.00 was collected for hotdogs hamburgers and soft drinks. all three coct $1.00 each. twice as many hotdogs were sold as hamburgers. three times as many soft drinks were sold as hamburgers. the number of soft drinks sold was?

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