Hello :3
To find your answer we need to subtract first because, a week is 7 days and it tells us he rented it for 10 days. So, 10-7=3, so d = 3.
Next, we need to multiply. So, $120 · 3 = $360.
Now time to add. $400 + $360 = $760.
So, it will cost $760 for a 10-day rental.
Hope This Helps!
Cupkake~
