Question: it takes 3 workers a total of 9 hours to build a giant machine with each worker working at the same rate . if 3 workers start to build the machine at 11 : 00 am , and one extra worker per hour is added beginning at 2 : 00 pm , at what time will the machine be complete ?
A)  5 : 15
B)  5 : 26
C)  5 : 37
D)  5 : 48
E)  5 : 59
Correct answer: b
Grade: 7 | Topic: Ratios and proportions | Difficulty: Hard | Standard: 7.RP.A.3