Question 976532
{{{R=3B}}}
.
.
.
{{{R+3B=900}}}
Substituting,
{{{R+R=900}}}
{{{2R=900}}}
{{{R=450}}}
Then,
{{{3B=450}}}
{{{B=150}}}
A plate of rice is 450 and a plate of beans is 150.