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.
The first option is correct
Answer:
#3 is 40
#4 is 90
Step-by-step explanation:
Answer:
(13+x)cm
Step-by-step explanation:
Given data
Length of sides
1cm, 5cm, 7cm
Since the shape is four-sided and the fourth side is not given, let the fourth side be x
so
The perimeter of the polygon is
P= 1+5+7+x
P= 13+x
Hence the perimeter of the polygon is
P= (13+x)cm
