Are you still looking to improve? At Q22, I suggest you begin with basic 10th-grade level math. Don't even think about the GMAT yet. GMAT tests fundamentals heavily and will destroy you if you're not up to scratch. If you're really passionate about doing an MBA, then it's going to be a long road to improvement but you will be able to stick with it. Begin by revising school-level Math and English. Khan Academy is a great, free resource for this. Please don't rush this part; take your time with it and build a solid foundation. Then, I suggest you drop a few $$ and enroll in an online tutoring program. Unstructured self-study helps those who already have a great grasp on the concepts. I suggest you save time and take no such risk. The $$ you spend will sting in the short term but will save you money on GMAT retakes. GMATClub has some fantastic offers on courses, and each course has a free trial. I personally used
e-GMAT and thought it was worth it; would highly recommend. This is a 7-8 month long journey you're about to take so mentally prepare yourself. The worst thing you could do is rush it by diving straight into solving
OG problems - it just won't work. Take it easy and be patient. Hope this helped.