You will need the Total Loan Cost Formula which is
(I'm having trouble attaching the graphic - I think the problem is with Brainly).
If nothing else, go to this web page.
It has a calculator and the formula.
http://www.1728.org/loanfrm4.htm
I get an answer of $6,238.70
The cost of one sandwich is $3.90
The cost of one deknk is $1.50
hopefully this is correct
Let the number be xy ,
xy = 10x + y. when reversed = yx = 10y + x
x = 2y ........(a)
10x + y + 10y + x = 66.........(b)
10(2y) + y + 10y + 2y = 66
20y + y + 10y + 2y = 66
33y = 66
y = 66/33
y = 2
x = 2y = 2*2 = 4
Recall the original number is xy = 42.