So in the picture, there is the working out I did (sorry for the bad writing). When you work out the question, remember to match the decimal points (I've done this in the pic). The answer I got was 1.20 but that is the same as 1.2.
The bike will cost $481.50 because 10% off of 500 is 50 so 500 - 50 = 450 Now include the sales tax which is 450 * 0.07 = 31.5 Now add the two totals to get $481.50