Which expression represents the number of hours in w weeks and d days? A. 7W + 12d
B. 84W + 24d
C. 168W + 24d
D. 168W + 60d

Work Shown:

w = number of weeks

d = number of days

1 day = 24 hours

1 week = 7 days

1 week = 7*24 hours = 168 hours

If 1 week is 168 hours, then w of them leads to 168w hours. The w is simply a placeholder for a number. For example, if 2 weeks go by, then w = 2 and 168*w = 168*2 = 336 hours have elapsed.

Then we add on 24d to represent the number of hours after d days have passed by. The variable d is the number of days. Like w, the variable d is also a placeholder.

We add up 168w and 24d getting 168w+24d. We don't have any like terms to combine, so we leave this as is.

-2 is the right