His per cent error is 16.¯^6%
Explanation:
Trent estimated his time to be 90m but the Actual time was 75m
Error was 90m−^75m=15m
A Fractional error was then 15m90m
So % error is 1590 ×100=1006%=16.¯^6%
If there are 10 wild cards there are 50 standard cards. 8 and 40 can both be divide by 4, which makes 2/10. This means that there are 2 wild cards for every 10 standard cards. If there are 50 wild cards, you simply multiply 2/10 by 5. This will give you 10/50. 10 wild cards in 50 standard cards.
P( two white) = 18/40 * 17/39 = 51/260
P( black then red) = 12/40 * 10/39 = 1/13
P( two black) = 12/40 * 11/39 = 11/130
P( white then black) = 18/40 * 12/39 = 9/65
The purpose of the quadratic formula is to easily obtain the x-coordinate of the vertex's location. The goal is to solve the equation by isolating x on one side of the equation, just like you would any other equation.
In step 7, take the square root of both sides. Note that you must account for the negative side of the square root, so add the +/- to the right side (not necessary for the left side because you want the x to be positive when you are finished, and you still get the same answer even if you assume the left side is negative).
Next, subtract b/2a from both sides and simplify the denominator of the root to be 2a.
Finally combine the terms to have a single denominator.