According to the question ,
So as per the question if we assume that the babysitter looked after the child for x hours in a week then , the total charge will be ,
→ Charge = $3/hr * x hr= $3x
So the total cost for a week , will be ,
→ Total cost = Base price + Charge
→ Total cost = $25 + $3x
And in the question we are told to assume total cost to be $C . Therefore ,
→ $C = $ (25 +3x)
→ C = 25 + 3x
Hence the required equation is C = 25 + 3x.
I hope this helps.