Answer: 1/9 of a mile per hour
=========================================================
Explanation:
6 & 3/4 = 6 + 3/4 = 24/4 + 3/4 = (24+3)/4 = 27/4
The work crew paves 3/4 of a mile in 27/4 hours. Divide those two fractions:
(3/4) divide (27/4)
(3/4) times (4/27)
(3*4)/(4*27)
3/27
1/9
The unit rate is 1/9 of a mile per hour. In other words, for each hour, they are able to pave 1/9 of a mile on average. So we should expect it takes about 9 hours to pave a full mile.
