A 15-person road crew is scheduled to finish repairing a highway in 12 days. On the morning of the fifth day, several new workers join the crew and, together, they complete the remaining repairs in 6 days. How many new workers joined the crew?

Answer 1

15 * 12 = 180
so
The whole job requires 180 man days

They worked for 4 days
so did 15 * 4 = 60 man days

they have 120 man days of work left
120 / n = 6
n = 20 men on the job

so 5 new men joined

Answer 2

no!!!! i didnt do it for free, they pay you money! jk the answer is 20/4, simplified is 5