John has invested a fraction 2/6 of his savings in an account that pays an annual interest rate of 5%, a fraction 5/28 in an account that pays an annual interest rate of 8%, and the rest in an account that pays an annual interest rate of 6%. What average return (in percentage terms) does John get on his total investment? If he earned $860 in interest, how much did he invest in each account? Solve the problem by first formulating an equation(s).