Question 1208043
t, for tea
s, for sugar


{{{system(6t+11s=13.30,11t+6s=17.30)}}}

Look at how the coefficients of t and s are arranged.  You might try just adding the corresponding members.


{{{(6+11)t+(11+6)s=13.3+17.3}}}

{{{17t+17s=30.6}}}

{{{t+s=30.6/17}}}

{{{t+s=1.8}}}