Question 186564
let t be three legged tables and f be four legged ones
{{{t + f = 36}}}
{{{3t + 4f = 124}}}
Use elimination
{{{t + f = 36}}}  multiply by 3
{{{3t + 3f = 108}}}
{{{3t + 4f = 124}}}   subtract
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-f = -16
f = 16
so t = 36-16 = 20

Does 3*20 + 4*16 = 124?