how many students got 90 or less = 14
how many students got more than 90 = 11
3 more students got 90 or less so answers is D. 3
please mark brainliest
Answer:

Step-by-step explanation:
Standard form is Ax + By = C, so we want x to be on the left side
To accomplish this, subtract 1/4x from both sides.

Multiply by -4 to get x to be equal to 1.

Answer:a = - 2
b = - 3
c = 3
Step-by-step explanation:
a + 5b - c = - 20 - - - - - - - - - 1
4a - 5b + 4c = 19 - - - - - - - - - 2
-a - 5b - 5c = 2 - - - - - - - - - - - 3
Adding equation 1 and equation 2, it becomes
- 6c = - 18
c = - 18/ - 6 = 3
Multiplying equation 2 by 1 and equation 3 by 4, it becomes
4a - 5b + 4c = 19
-4a - 20b - 20c = 8
Adding both equations, it becomes
- 25b - 16c = 27
- 25b = 27 + 16c = 27 + 16 × 3
- 25b = 75
b = 75/- 25 = - 3
Substituting b = - 3 and c = 3 into equation 1, it becomes
a + 5 × - 3 - 3 = - 20
a - 15 - 3 = - 20
a - 18 = - 20
a = - 20 + 18 = - 2
Answer:
Step-by-step explanation:
5 red
15 black
10 white
altogether the is 30 marbles so that means it is 'out of' 30
and because the is 5 red it would be 5/30
and because the is 10 white it would be 10/30
that should be the answer but if you have to work the total all together then it would be 15/30
hope this helps :)