O número 2021 tem resto 5 quando dividido pelo nmr 6, 7, 8, e pelo nmr 9. Quantos múmeros inteiros positivos menores do que 2021 têm essa propriedade?

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters