Step-by-step explanation:
ALGEBRA 1
Lilly S. asked • 08/16/17
3 girls get volunteer hours.
Katie, Elizabeth, and Siobhan voluenteer at the hospital. In a week, Katie volunteers 3 hours more than Elizabeth does and Siobhan volunteers 1 hour less than Elizabeth. Over 3 weeks, the number of hours Katie volunteers is equal to the sum of Elizabeth's and Siobhan's volunteer hours in 3 weeks.
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Andy C. answered • 08/16/17
TUTOR 4.9 (27)
Math/Physics Tutor
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We know nothing about Elizabeth hours, so that is where you assign the variable.
Elizabeth = X
Katie = X+3
Siobhan = X -1
Assuming this holds true over 3 weeks,
3(x+3) = 3X + 3(x-1)
3x + 9 = 3x + 3x - 3
3x + 9 = 6x - 3
0 = 6x - 3 - 3x - 9
0 = 3x - 12
12 = 3x
x=4
in one week:
Elizabeth volunteers 4 hours
Katie volunteers 7 hours
Siobhan volunteers 3 hours
over three weeks:
Elizabeth volunteers 12 hours
Katie volunteers 21 hours
Siobhan voluteers 9 hours
21 = 12 + 9, so yes it checks.
