Person 1 can do a certain job in 21 minutes, and person 2 can do the same job in 28 minuets. when completing the job together, which expression would be used to represent the amount of work done by person 1. 21,1/21,x/21,21x

1/21.

Step-by-step explanation:

To solve the problem 'How long would they take to do the job working together?'  you would work in fractions of the job done / minute:

1/21 + 1/28 = 1/x.

So for person 1 the expression is 1/21.

a. turk and mcalister

b. howard, mission, and market

c. yes. since streets end some do not cross yet are not parallel to others. example: mcalister and 5th

step-by-step explanation:

parallel lines are lines which do not intersect ever and look a lot like railroad tracks. turk, mcalister and golden gate are examples of these.

intersect are streets which cross each other and a car on one can reach the other. howard, mission, and market intersect with 6th.

skew lines are lines which neither intersect nor are parallel. these lines exist here because some streets end and never intersect another like mcalister and 5th.