You do not need to find the amount total, because the sales tax was added before the tip. What was the amount of sales tax? The group gave a generous tip when they calculated it on the tax-in price.
I know that 37.50 was the price without tip or tax. Correct
I also know that 8% was added for tax and 18% was added for tip. Correct
I know I need to know how to find the amount total in dollars. Nope
Since the tax was added to the bill first, you will only need to calculate the tax amount in dollars.
The added tax is
This is solving worded problems in pre-algebra.