Aconstruction firm is trying to decide which of two models of a crane to purchase. model a costs $100,000 and requires $4,000 per year to maintain. model b has an initial cost of $78,000 and a maintenance cost of $13,000 per year. for how many years must model a be used before it becomes more economical than b? (round your answer to one decimal place.)

On the way home from visiting his family, vincent’s plane cruised at an altitude of 3.2 × 10^4 feet. he had heard that a man named felix baumgartner skydived from an altitude of 1.28 × 10^5 feet. vincent wants to know how much higher felix went on his skydiving trip. question 1 you have already seen how adding numbers works in either scientific notation or standard notation. but can you subtract numbers in scientific notation and get the same results as subtracting in standard notation? to find out, first solve vincent’s problem in standard notation. part a write the cruising altitude of vincent’s plane in standard notation.