Final answer:
To find the total number of customers who took the survey, divide the number of customers who rated the shop as 'very satisfactory' by the percentage (expressed as a decimal). The calculation is 166 divided by 0.4, resulting in 415 customers.
Step-by-step explanation:
The student's question involves finding the total number of customers who took a survey if 166 customers represent 40% of the total. To find the total number, we use the concept of percentages. The equation we can set up is:
Total Number of Customers = Number of Customers who rated 'very satisfactory' / (Percentage / 100)
Therefore:
Total Number of Customers = 166 / (40 / 100) = 166 / 0.4 = 415
The correct answer is (c) 415 customers took the survey.