SEAMO 2017 — Paper D — Grade 7–8 Question 3

Question 3

Coffee types A and B cost forty and sixty dollars per kg and are mixed in mass ratio $m:n$. A’s price decreases $15\%$, B’s increases $15\%$, while mixture cost remains unchanged. Find $m:n$.

$1:2$
$2:3$
$3:2$
$2:1$
$5:2$