James completed 18 math problems this is 30% of the problems he has to do many math problems must he do

Your question is not clear because of the grammar used. So I was only able to come up to this solution: 30/100 multiply by x gives us 18. So x = 60. The total math problems are 60. James solved 18 (30% of 60) now he needs to solve 70% remaining of the 60 problems. So 60 - 18 = 42.