Regular price: $419
Sale price: (1-0.205)($419) = $333.11
The bike will cost $333.11 before tax. You haven't shared the tax rate, but I can at least tell you that the cost of the bike after tax will be
(1.00 + rate as a decimal fraction)*$333.11.
Example: If the tax rate is 7.5%, then the bike will cost (1.00+0.075)*($333.11).
12 = 30% of what
12 = 0.30x
12 / 0.30 = x
40 = x.......so 12 is 30% of 40
In this problem, it is important to take note that the number of numbers to be utilized isn't specified so it can be up to a thousand numbers. It wasn't also specified if repeating of numbers is allowed or not. So with those taken into consideration and the condition presented in mind, the numbers that can give you 8 when added and 30 when multiplied are 2, 3, 5, -1, and another -1. The derivation from this is mainly from factorization and a little bit of logic.
here is the solution.
2 x 3 x 5 x -1 x -1 = 30
6 x 5 x -1 x -1 = 30
30 x -1 x -1 = 30
-30 x -1 = 30
30 = 30
2 + 3 + 5 + -1 + -1 = 8
5 + 5 + -1 + -1 = 8
10 + -1 + -1 = 8
9 + -1 = 8
8 = 8
