First we gather all the information we have about the amount of miles that Carolyn runs:
Monday, Wednesday, Friday: 4 1/2 miles
Tuesday, Saturday: 2 3/4 miles
And the question is the amount of miles that she runs in 4 weeks.
So lets begin by calculating the amount of miles she runs in one week, then we just multiply by 4 and we'll have the final answer.
So, we have to add 4 1/2 three times (Monday, Wed, Friday), and 2 3/4 two times (Tuesday, Sat):
1 week Miles = 4 1/2 + 4 1/2 + 4 1/2 + 2 3/4 + 2 3/4
lets add the whole parts and the fraction parts apart:
1 week Miles = (4 + 4 + 4 + 2 + 2) + (1/2 + 1/2 + 1/2 + 3/4 + 3/4)
1 week Miles = (16) + (3/2 + 6/4)
we can reduce the last fraction:
1 week Miles = (16) + (3/2 + 3/2)
1 week Miles = (16) + (6/2)
1 week Miles = (16) + (3)
1 week Miles = 19
therefore Carolyn runs 19 miles each week, so for 4 weeks we have to add 19 four times or multiply it by 4, is the same:
4 weeks Miles = 4*19
4 weeks Miles = 76
hence Carolyn runs 76 miles in 4 weeks.
