Question 1183664
Strange description.
If "Bill is 5 times older than Keira, Bill is 5 times older than Phil,", then Keira and Phil are the same age.

<pre>
Bill        k+5k=p+5p
Keira       k
Phil        p
Oscar      2(k+5k)=2(p+5p)
TOTAL       81
</pre>
That table can be simplified because the simple addition and k=p.

<pre>
Bill        6p
Keira       p
Phil        p
Oscar       12p
TOTAL       81
</pre>
Question asked essentially for p.