In an economy, there are only two industries, mining and manufacturing. And it has been observed that a 10% rise in mining and a 20% rise in manufacturing can benefit the economy by 18% , but in a year, if the manufacturing industry as risen by 10%, and the economy has still risen by 18%, how much rise should have been observed in the mining industry.
My approach: ($E$- Economy, $M$- Mining, $F$- Manufacturing)
$E= M+F$ - (1)
$1.18E= 1.1M+1.2F$ - (2)
$1.18E= xM+ 1.1F$ -(3)
However, this is not very plausible. How should I go further.