Problema Solution

Sue and Lois live 13.5 km apart. At 10:00AM each girl leaves her house and jogs toward the other. The ratio of Sue's speed to Lois's speed is 5:4. If the girls meet at 11:45AM how fast does each girl jug?

Answer provided by our tutors

The time that the girl spend jogging is:

t = 1 hr 45 min = 1 + 45/60 =  1.75 hr

The distance is:

d = 13.5 km 

Let

v1 = Sue's speed

v2 = Lois/s speed

v1 : v2 = 5 : 4

4v1 = 5v2

Since distance = speed*time and the they jog toward each other we can write:

v1t + v2t = d

1.75v1 + 1.75v2 = 13.5

We have the following system of equations:

4v1 = 5v2

1.75v1 + 1.75v2 = 13.5

........

click here to see the system of equations solved for v1 and v2

........

v1 = 4.29 km/hr

v2 = 3.43 km/hr

Sue's speed is 4.29 km/hr.

Lois/s speed is 3.43 km/hr.