3a. Jackson's gross pay for 40 hours is (40 h)×($12.20/h) = $488.00
3b. An equation for Jackson's pay could be 372.10 = h×12.20 This can be solved for h by dividing by 12.20 372.10/12.20 = h = 30.5 Jackson worked 30.5 hours last week.
3c. The total of hours shown is (8) + (7 1/4) + (8 1/2) = (8 +7 +8) +(0.25 +0.50) = 23.75 The number of hours missing is the difference between this number and the hours found in part (b). 30.50 - 23.75 = 6.75 There are 6 3/4 hours missing from Jackson's time sheet for last week. This is less than a full day's work, so seems reasonable.
_____ Of course, you know the decimal - fraction conversions: 1/4 = 0.25 1/2 = 0.50 3/4 = 0.75
