The value of s is 4.
First, substitute 10 for r into the equation.
3r=10+5s
3(10)=10+5s
30=10+5s
Now the equation can be solved as normal. Subtract 10 from both sides of the equation to isolate s.
30-10=10-10+5s
20=5s
Divide 5 on both sides.
[tex] \frac{20}{5} [/tex]=[tex] \frac{5s}{5} [/tex]
4=s