A software author invests his royalties in two accounts for 1 yr.

(a) The first account pays 2% simple interest. If he invests x dollars in this account, write an expression for y₁ in terms of x, where y₁ represents the amount of interest earned.

(b) He invests in a second account $500 more than he invested in the first account. This second account pays 1.5% simple interest. Write an expression for y₂, where y₂ represents the amount of interest earned.

(c) What does y₁ + y₂ represent? 

(d) How much interest will he receive if $250 is invested in the first account?