SEAMO 2018 — Paper E — Grade 9–10 Question 17

Question 17

Barrel $A$ contains $11$ litres of alcohol and barrel $B$ contains $15$ litres of water. Some alcohol is poured from $A$ to $B$, then some well-mixed liquid is poured back from $B$ to $A$. The final alcohol percentages are $62.5\%$ in $A$ and $25\%$ in $B$. How many litres are poured back?

$6\,\mathrm l$
$6.2\,\mathrm l$
$7\,\mathrm l$
$7.3\,\mathrm l$
None of the above