Step-by-step explanation:
Selling price = Rs.80
Cost price = Rs.100
here, CP > SP
Now...
Loss ( L ) = CP - SP
= RS.100 - 80
= Rs.20
Now...


= 20 %
His budget is $5000
you take 800 and divide it by 0.16
gives you 5000
-12 because surface is usually considered as "0" so 12 ft below the surface means -12.
0.1 recurring as a fraction would be 1/9