Answer:
9
Step-by-step explanation:
Cross Multiply: 
Simplify: 4x=36
x=9
TOTAL IS $10
If the party costs $5 and each additional person is $1 and she invites 5 more 5 X 1 = 5
OR 1 + 1 + 1 + 1 + 1
Answer:
y is also doubled.
Step-by-step explanation:
Direct proportionality between
and
means that

or
,
which indicates a linear relationship between
and
because they are related by a constant.
Therefore, if x is doubled, then the new value of
is 



The new value of
is 2 times the previous; therefore,
is doubled as
is doubled.
Answer:
0.75 points per minute
Step-by-step explanation:
9/12 is 0.75