Question 328290
Let B be the number of blue marbles, R red.
1.{{{6B=2R+18}}}
2.{{{5B=6R-2}}}
From eq. 1,
{{{B=R/3+6}}}
Substitute into eq. 2,
{{{(5/3)R+6/5=6R-2}}}
Multiply both sides by 15.
{{{25R+18=90R-30}}}
{{{65R=48}}}
R is not an integer value which it must be.
Check the problem setup.
"three times the number twice of blue marbles" 
Is this correct? Three times twice is 6 times.