Answer: y
=
18
Explanation:
As
y
varies directly as
x
, we have
y
∝
x
. Also it varies inversely as square of
z
, which means
y
∝
1
z
2
.
Hence,
y
∝
x
z
2
or
y
=
k
×
x
z
2
, where
k
is a constant.
Now when
x
=
80
and
z
=
4
,
y
=
10
, so
10
=
k
×
80
4
2
=
k
×
80
16
=
5
k
Hence
k
=
10
5
=
2
and
y
=
2
x
z
2
.
So when
x
=
36
and
z
=
2
,
y
=
2
×
36
2
2
=
72
4
=
18
Step-by-step explanation:
