Smart way to make money!!!

Okay so mathematically speaking harvesting corn is much faster than planting onions or whatever. Cuz it takes I think 7 hours to harvest one crop of onions. Where if you pay attention to your notification sims gives you. You can plant an maks the same amount of money off corn in only 3 hours because it it pays 100 bucks every 20 minutes. So do the math an harvest corn an in 7 hours you will have twice the amount of money than harvestin onions. Your welcome lol.