How to expand and simplify the sum of 1/i^3

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Your client has saved $1,860 for a down payment on a house. a government loan program requires a down payment equal to 3% of the loan amount. what is the largest loan amount that your client could receive with this program

Val and tony get paid per project. val is paid a project fee of $44 plus $12 per hour. tony is paid a project fee of $35 plus $15 per hour. write an expression to represent how much a company will pay to hire both to work the same number of hours on a project.