SOLUTION: Two girls are 60 miles apart. Leaving at the same time, mary will travel 21 miles/hr and sally will travel 15miles/hr. when will the meet. Please help with the formula. PL

Question 13066: Two girls are 60 miles apart. Leaving at the same time, mary will travel 21 miles/hr and sally will travel 15miles/hr. when will the meet. Please help with the formula.
PL
Answer by glabow(165) (Show Source): You can put this solution on YOUR website!
Assume you know where they will meet and call it M. How long does it take Mary to get to M? The answer is 21 mi/hr times x hours. So, we have
21x = M
How long does it take Sally to get to M? The answer is that she must travel the distance that takes her to M starting at 60 mi. And that is 60-M. So, we have
15x = 60-M
Substituting the value of M from the first equation into the second we get
15x = 60 - 21x
36x = 60
x = 5/3
This says that after 5/3 of an hour Mary will have travelled 35 miles (21 x 5/3) and
Sally will have travelled 25 miles (15 x 5/3).
Checking: 35 miles + 25 miles = 60 miles.

RELATED QUESTIONS
Write an equation and solve each problem. Two buses leave Bethlehem at the same time and... (answered by macston)

two high speed ferries travel to same island. One at 32 miles per hour and the other at... (answered by harpazo)

two planes leave an airport the same time and travel in opposite directions. one plane... (answered by lwsshak3,richwmiller)

two buses leave a station at the same time and travel in opposite directions one bus... (answered by lwsshak3)

two planes travel toward each other from cities that are about 1463 km apart at rates of... (answered by rajagopalan)

Two planes travel towards one another from cities that are about 450 km apart at rates of (answered by nerdybill)

Two cars start at the same place at the same time and travel in opposite directions at... (answered by ikleyn)

Two cyclists , one averaging 10km/hr and the other 12km/hr, start from the same town at... (answered by Boreal)

two boys on bicycles start from the same place at the same time.One rides at 15km/hr, and (answered by jorel1380,rwm)