If pg=50 and gr =15,then what is the value of g(p+r)

We are asked to solve for the value of g(p+r) when pg=50 and gr=15. The solution is shown below:
pg is the same with gp
pg = gp
gr is the same with rg
gr=rg
Hence, we have:
g(p+r) , distributive property
gp + gr = pg + gr = 50 + 15 = 65

The answer is 65.