Let b and r be the price of a loaf of bread and a roll respectively.

We have :

\(\left\{{}\begin{matrix}b+6r=1.8\\2b+4r=2.4\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}b+6r=1.8\\3b+6r=3.6\end{matrix}\right.\)\(\Rightarrow2b=1.8\Rightarrow b=0.9\)

Hence,one loaf of bread costs 0.90

let b an r be the price of a loaf of bread and a roll respectively.

Now we have:

_b+6r = 1.8

_2b+4r = 2.4

=>

_b+6r=1.8

_3b+6r=3.6

=>2b=1.8 and b=0.9

Hence, one loaf of bread costs 0.90