20-Determine cuanto tiempo debe transcurrir para que un capital de 6209 $ colocado al 10 % anual de interés con capitalización cuatrimestral, produzca un monto de 10000 $. (Rta.: 4 años, 10 meses y 3 días)

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

step-by-step explanation:

no, her answer is not correct.   we square the lengths of all sides and then determine whether the pythagorean theorem holds here:

9² + 15² = 306.   this is not equal to the square of the longest side ( that square being 395.   answer c is correct.

answer is b

step-by-step explanation: