Question 327171
30 tons of rock cost 30(50)=$1800.
You then have $2500-$1800=$700 left to buy trees.
{{{30(60)+N(84)<2500}}}
{{{1800+84N<2500}}}
{{{84N<700}}}
{{{N<700/84}}}
.
.
.
{{{N=700/84=8.33}}}
You can buy at most 8 trees after you bought the rock.