I had a doubt regarding a question. My answer is coming as 10 even though I've tried using another method and according to my book, the answer is as 7.5. Can anybody help if possible? (Also, hope we are allowed to ask homework questions here, if not please let me know).
X varies inversely with y and y varies inversely with z. When x=30, the values of y and z are 15 and 10 respectively. What is the value of z, when x=22.5 and y=20? (I took x as directly proportional to z/y and found out the constant of proportionality and solved accordingly which gave me 10 as the answer)
Hint:
When $x$ goes from $30$ to $22.5$, it is multiplied by $\frac34$.
When $y$ goes from $15$ to $20$, it is multiplied by $\frac43$.
When $z$ goes from $10$ to $?$, it is multiplied by $\frac34$.
Note: if $xy=C$ and $yz=D$ then $x/z=C/D$ is constant.