1) The number is 12.
2) There are 7 passengers in a row.
3) Carol, Xavier and Keela drank 580, 1160 and 1260 mL of water, respectively.
<h3>How to resolve word problems involving linear equations</h3>
In this question we find word problems involving linear equations, in each case we need to understand the statement, derive mathematical equations and looking for corresponding solutions by algebraic means. Now we proceed to solve for each case:
Case 1
A variable is found herein and we need to resolve on this linear equation: (x - A number)
(x + 8) / 4 = 1 + (1 / 3) · x
(1 / 4) · x + 2 = 1 + (1 / 3) · x
1 = (1 / 12) · x
x = 12
The number is 12.
Case 2
A variable is found herein and we need to resolve on this linear equation: (x - Number of passengers per row)
30 · x + 12 = 222
30 · x = 210
x = 7
There are 7 passengers in a row.
Case 3
Three variables are found herein and we need to resolve on these linear equations: (x - Water consumed by Carol, y - Water consumed by Xavier, z - Water consumed by Keela)
z = 2 · x (1)
y = z + 100 (2)
x + y + z = 3000 (3)
Finally, we find the solution of this system:
x + (z + 100) + z = 3000
x + 2 · z = 2900
x + 4 · x = 2900
5 · x = 2900
x = 580 mL
z = 1160 mL
y = 1260 mL
Carol, Xavier and Keela drank 580, 1160 and 1260 mL of water, respectively.
To learn more on systems of linear equations: brainly.com/question/21292369
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