15 last year, jora spent
30% of his salary on rent
of his salary on entertainment
of his salary on living expenses.
he saved the rest of his salary.
jora spent £3600 on living expenses.
work out how much money he saved.

Write the pair of fractions as a pair of fractions with a common denominator

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

Find the zeros of each function. f(x) = x^2 + 5x - 6