If she ran one mile in an hour wouldn't that mean her unit rate is one mile per hour? I think that's right but ask your teacher for reinsurance.
D (7) should be the correct answer.
60 kilometers because it is 2 cm just multiply by 2
Let x = the amount of time that the third person needs to work on the job to add up to one
1 = 1/2 + 1/3 + x
1 - 1/2 - 1/3 = x
To subtract the fractions we need to put them all over a common denominator. Let's use 3*2 = 6 as the denominator; so 1 = 6/6, 1/2 = 3/6, 1/3 = 2/6:
6/6 - 3/6 - 2/6 = x
1/6 = x
The third person must work 1/6 time on the project.