47. $4000 invested at 4%, $6000 invested at 5%, and $10,000 invested at 6%
49. Alex worked 2 hours, Becky worked 2.5 hours, and Courtney worked 1.5 hours.
51. 56 nickels, 225 dimes, and 19 quarters
53. 31 hours for normal daytime work, 14 hours at night, and 8 hours on a holiday
55. Cell A contains healthy tissue
57. Cells A, B, and C contain healthy tissue (because