The equation of a circle with a center of (h,k) with a radius of "r" is
looking at the given equation,
5x^2 +5y^2=20
divide 5 to both sides to get
x^2+y^2 =4
now compare that to the equatio of a circle shown above
1 in 38.
Nothing much to say about this problem. There are 38 spaces on the roulette wheel and an every space on a fair wheel has an equal probability of being selected. So you would expect 1/38 = 0.026315789 = 2.6315789% of the time for the number 21 to show up.
I'm not sure but maybe the answer is :
68 / 74 = 0.919
Well, you would multiply the tip by the original bill, which is 10.80 and then add that to the bill which is going to be $70.80.
Next for the the tax you would multiply 7 by 60, which is $4.20 in tax
Lastly you just add the tax and the tip to the bill which equals.
$75.00