Question 1142129
L, price of oil
p, price of petrol


{{{system(3L+30p=45,7L+15p=40)}}}


{{{3L+30p-14L-30p=45-80}}}
{{{-11L=-35}}}
{{{highlight(L=35/11)}}}{{{R}}}


{{{highlight(3&2/11)}}}{{{R}}}