i want to add increment of 6% to the return result from the query - asp.net

Question

<td>
<strong>
Rs #(Model.lstItem.Sum(c => c._product.option != null
? (c._product.option.Price * c.Quantity)
: (c._product.product.Price * c.Quantity))
- (Model.coupon != null ? (int)Model.coupon.Discount : 0))
</strong>
</td>
first of all let me tell you i am totally new in asp.net mvc..
Now my question is i have the above query which is returning total after multiplying price and quantity. now what i want is i want to increment 6% of pricequantity to the pricequanity..
The final result will be like (price * quantity) + 6% of price * quanity..
i hope you guys understand my question

Answer 1

You can just do this:
(price * quantity) + (((price * quantity)/100) * 6))

Answer 2

You shouldn't keep these constants in the View. If you have these calculations in multiple places and you wanted to change the percentage to 7% in the future, you'd have to change everywhere. So, it should either come from your database, or a config file or a constants class.
So, the easiest way to do this is to create a static class called ApplicationConstants in a Common folder or Utility folder.
public static class ApplicationConstants
{
public const int ProfitPercentage = 6;
}
Then in your View,
#using YourAppName.Common
<td>
<strong>
Rs #(
(1 + ApplicationConstants.ProfitPercentage / 100) *
(Model.lstItem.Sum(c => c._product.option != null
? (c._product.option.Price * c.Quantity)
: (c._product.product.Price * c.Quantity)))
- (Model.coupon != null ? (int)Model.coupon.Discount : 0))
</strong>
</td>