A student earned a grade of 80% on a math test that had 30 problems. How many problems on
this test did the student answer correctly?

The problems on the test the student got correctly is 24.

Percentage can be described as a fraction of a number expressed as a number out of hundred.

80% of the questions were gotten correctly.

Number of questions gotten corrected = percentage gotten currently x number of questions

80% x 30

= 0.8 x 30 = 24.

To learn more about percentages, please check: link

24 problems

Step-by-step explanation:

equation: 80/100 = x/30

cross multiply: 100 * x = 80 * 30

multiply: 100x = 2400

divide each side by 100: x = 24

24 problems

I hope this helped, please mark Brainliest, thank you !!

{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