a mobile phone company charge for a local call such that $0.5 in the first minute and $0.3 every minute there after. Find a formula for the total amount charged for call lasting in x minutes
Have you studied the Least Integer Function (sometimes called a step function)? https://www.khanacademy.org/math/algebra/algebra-functions/piecewise-functions/e/evaluate-step-functions-from-their-graph
