David rolls a number cube fifty times. The number 4 comes up twelve times. The number 3 comes up eight times. What is the experimental probability of rolling a 3 or 4? *
1 point
20%
30%
40%
50%

40%.

Step-by-step explanation:

Prob( Rolling a 4) = 12/50

Prob( Rolling a 3) = 8/50

When the combined probabilities contain  an 'OR' we Add the probability values:

Probability of a 3 or a 4  

= 12/50 + 8/50

= 20/50

= 2/5

= 40%.

answer

a the answer hopes this

step-by-step explanation:

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1