Andrew M. answered • 03/01/16

Tutor

New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors

**distance = rate*time, d= rt**

If Briana travels x miles

Zoe travels 207-x miles

Briana travels r mph

Zoe travels r+9 mph

Time = 9 hours

Plugging both into the distance formula:

Brianna: x = 9r

Zoe: 207-x = 9(r+9)

Substitute 9r in place of x in 2nd equation to solve for r

207-9r = 9r+81

207-81 = 18r

126 = 18r

r = 7 mph

**Brianna travels at 7 mph**

**Zoe travels at 7+9 = 16 mph**

Check Answer:

Together they should travel 207 miles

Zoe: 9(7) = 63 miles

Brianna: 9(16) = 144

Zoe + Brianna = 207 miles