The first thing we must do is define a variable.
We have then:
x: Linda's speed.
Then, by definition, the time traveled is equal to the distance between the velocity.
We have then:
For Linda:
For Miguel:
Then, since time is the same, then:
Clearing Linda's speed we have:
Then, Miguel's speed is:
Answer:
Linda's speed is 10 Km/h
Miguel's speed is 14 Km/h
The two problems are almost identical: you have to set up a system, and then solve it.
In the first case, let and
be, respectively, the number of girls and boys.
We know that (the number of girls in the Spanish Club is four more than twice the number of boys). Also, we know that
(there are 61 students in total).
So, we have the system
We can use the first equation to substitute in the second
And then solve for :
For the second problem, let and
be the number of pins knocked down by, respectively, Carrie and John. Just like before, we have the system
And you can solve it in the very same way we solved the previous one.