1. Keith's Sheet Music needs a program to implement its music teacher's discount policy. The program is to prompt the user to enter the purchase total and to indicate whether the purchaser is a teacher. The store plans to give each customer a printed receipt, so your program is to create a nicely formatted file called receipt.txt. Music teachers receive a 10% discount on their sheet music purchases unless the purchase total is $100 or higher. In that case, the discount is 12%. The discount calculation occurs before addition of the 5% sales tax. Here are two sample output files-one for a teacher and one for a nonteacher. Total purchases $ 122.00 Teacher's discount (12%) 14.64 Discounted total 107.36 Sales tax (5%) 5.37 Total $ 112.73 Total purchases Sales tax (5%) Total $ 24.90 1.25 $ 26.15 Note: to display a % sign, place two % signs in the format string: printf("%d%%", SALES_TAX); 2. The rate of decay of a radioactive isotope is given in terms of its half-life H, the time lapse required for the isotope to decay to one-half of its original mass. The isotope cobalt-60 (Co) has a half-life of 5.272 years. Compute and print in table form the amount of this isotope that remains after each year for 5 years, given the initial presence of an amount in grams. The value of amount should be provided interactively. The amount of 60 o remaining can be computed by using the following formula: r = amount x C /H) where amount is the initial amount in grams, C is expressed as e-0.693 (e = 2.71828), y is the number of years elapsed, and H is the half-life of the isotope in years. vorhe manier ter hele momentin arms, Cise