Answer: −1.409
Step-by-step explanation:
Probability of drawing 3 hearts: 13/52 * 12/51 * 11/50 = 0.013
Probability of drawing 3 black cards: 26/52 * 25/51 * 24/50 = 0.118
Probability of other draw: 1 - 0.013 - 0.118 = 0.869
0.013 * (50 - 5) = 0.585
0.118 * (25 - 5) = 2.353
0.869 * (0 - 5) = -4.347
Expected value: 0.585+ 2.353 - 4.347 = -1.409
Serach it, Thats what I did!
Even though we don't know the number yet, we need to give it some kind of label
so that we can work with it. We can call it anything. I'd like to call it ' G '.
The number we're looking for is ' G '.
Half of it is 1/2 G
The sum of that and 6 is 1/2 G + 6
Ten times that is 10 (1/2 G + 6)
The question says that's 8.
So 10 (1/2 G + 6) = 8
Divide each side by 10 : 1/2 G + 6 = 0.8
Subtract 6 from each side: 1/2 G = - 5.2
Multiply each side by 2 : G = - 10.4
That seems like a weird answer. We should check it.
The number: -10.4
Half the number: - 5.2
The sum of half the number and 6: -5.2 + 6 = +0.8
Ten times that sum: 8
Yep ! By golly, sho nuff, dV-dT and E to the X !
Everything checks out, and the mystery number is - 10.4
Answer:
1 1/2
Step-by-step explanation:
X represents the number that would be added to the silver cars.
x/40= 4
X=40x4
x=160
Subtract the given 20 from 160 because 160 is the total number
160-20=140
Therefore 140 would be added to 20 silver cars to get the ratio1:4
