human
Write a formula to describe a situation Sally the electrician charges a call-out fee of \( £ 40 \) and then \( £ 15 \) per hour that the job takes.

If a job takes \( n \) hours, which formula would help work out the cost \( (C) \) of hiring Sally? \( C=15 n \)
gpt
Does not add on the constant in a worded substitution problem