Question:
When y is 4, p is 0.5, and m is 2, x is 2. If x varies directly with the product of p and m and inversely with y, which equation models the situation?
xpmy=8
xy/pm=8
xpm/y=0.5
x/pmy=0.5
Answer:
The equation models the situation is
![(x y)/(p m)=8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fxoq7m7twk5vx5z4emt9unzcqhtsbdtn6k.png)
Solution:
Given that
x is 2, y is 4, p is 0.5, and m is 2
x varies directly with the product of p and m
x varies inversely with y
![\text {Product of } p \text { and } m=p * m=p m](https://img.qammunity.org/2020/formulas/mathematics/middle-school/u4ykcm4gd3lj4obvg634cmll1ti7nf7xwb.png)
x varies directly with the product of p and m
---- eqn 1
As x varies inversely with y,
----- eqn 2
From (1) and 2, we can say that
![x \propto (p m)/(y)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2d0t8e4loq6z9hncruguzq2mnh3rd478mb.png)
![\Rightarrow x=k (p m)/(y)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jdrh31wn6osjypjgukj5ufqxhijhu6qx5n.png)
where k is constant of proportionality
---- eqn 3
On substituting given values of x = 2, y = 4, p = 0.5 and m= 2 in eqn (3) we get
![(x y)/(p m)=(2 * 4)/(0.5 * 2)=k](https://img.qammunity.org/2020/formulas/mathematics/middle-school/n3gjymmaaxiv11o7en7123aifycjfztrl1.png)
![\begin{array}{l}{(x y)/(p m)=(8)/(1)=k} \\\\ {=>(x y)/(p m)=8}\end{array}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7aclgd5pswsfd59934b8aze1l17sm5m1l5.png)
Hence correct option is second that is
![(x y)/(p m)=8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fxoq7m7twk5vx5z4emt9unzcqhtsbdtn6k.png)