Hi. I don’t understand why there is a number ‘1’ in the calculation to find the split in lesson 6’s challenge (1 + tax). Can anyone help explain this? Thank you so much.

/*Challenge:

4 people have dinner and want to split the bill.

Calculate the total with tax and then how much each person owes.

Assign it to the variable, ‘split’ and then print it out to the console area.

*/

let people:Double = 4

let subtotal:Double = 128

let tax = 0.13

var split:Double = 0

// Solution

split = (subtotal * (1 + tax))/people

print(split)

36.16