Answer:
The friends will each have passed _33_ scales in _7_ weeks.
Step-by-step explanation:
We must write an equation for the number of scales that Nick approves and an equation for the number of scales that Mary approves.
For Nick we have:
5 initial scales
Nick has committed to approve 4 scales per week. Let's call x the number of weeks.
So the number of scales and for Nick is:
[tex]y = 5 + 4x[/tex]
For Mary we have:
12 initial scales
Mary has committed to approve 3 scales per week. Let's call x the number of weeks.
So the number of scales and for Mary is:
[tex]y = 12 + 3x[/tex]
To know when the two friends have passed the same number of scales we must equal both equations and solve for x:
[tex]12 + 3x = 5 + 4x[/tex]
[tex]12-5= 4x-3x[/tex]
[tex]x= 7\ weeks[/tex]
And
[tex]y=12+3*7\\\\y=33\ scales[/tex]