If you understand the concept, it would be very easy for you!
1.) First, convert the 30% to a real mathematical number (decimal) So it would be 0.30.
2.) Find out what 30% of $55 is. This is the amount of the sale discount.
0.30 * $55 = $16.50 This is the cost off, not the final cost.
3.) Then, just minus the cost off from the usual price. $55.00 - $16.50 = $38.50
4. But not done yet! We still have to find the sales tax. 7% is still not a mathematical number, so convert it to a decimal. 7% = 0.07
5.) Now, multiply the 0.07 by the discount price. 0.07 * 38.50 = 2.695. That is not the total, obviously, but it is the tax bill.
6.) Simply add the tax bill to the discounted. So it is 2.695 + 38.50, which gives you the final answer!!
7.) You got $41.195, correct? But we have to round it.
ANSWER: $41.20