1.
If
y
varies jointly as the square of
x
and the cube of
z
and
y
= 9 when
x
= 3 and
z
= 4, find
y
when
x
= 8 and
z
= 5.
A.
100
B.
45
C.
125
D.
40
Hint
2.
Use
y
=
to find the value of
y
when
x
= 14.
A.
8
B.
56
C.
28
D.
98
Hint
3.
If
y
varies directly as the square root of
x
and
x
= 25 when
y
= -15, find
x
when
y
= -108.
A.
x
= 4500
B.
x
= 6
C.
x
= -5
D.
x
= 1500
Hint
4.
If
y
varies inversely as the cube of
x
and
y
= 8 when
x
= 2, find
x
when
y
= 1.
A.
x
= 8
B.
x
= 4
C.
x
= 2
D.
x
= 1
Hint
5.
Dakota wants to cook a meal for his family. He knows that the more people who help, the less time it will take to prepare the food. Write an equation that represents this situation. Let
C
be the cooks in the kitchen,
T
be the time and
k
as the constant of variation.
A.
k
=
C
T
B.
T
=
kC
C.
C
=
kT
D.
k
=
CT
Hint