Find the total amount from a given percentage and x amount which on substraction provides the x amount I am a freelancer and working with a firm. I provide services, for which I am taking extra 5% as service charge of the firm's amount. Suppose the firm's amount is 600, and I am chargin 5%. 600 + 600%5 = 630 This total amount (`630`) again goes to a payment service gateway where they (firm) have already programmed to deduct their share and settle my share (`5%`). So what happens on payment service gateway is they deduct 5% from the total amount (`i.e., 630`) and not from the firm's actual amount (`i.e., 600`). 630 - 630%5 = 598.5 As you can see, their share (598.5) reduces by the actual amount (600). Could you please help me how to produce the total amount to the payment gateway server so that the firm gets their full amount, and I get my 5%. I guess i.e., total_amount - total_amount %5 = firm_amount

To lay out your comment:

When the payment service gateway deducts $5\%$ of the total payment, they return $95\%$ of the total payment to the firm. So you have $$\text{Firm's net receipt } = \text{Total payment } \times \frac{95}{100}$$ and can find the total payment by dividing both sides by $\frac{95}{100}$ to give $$\text{Total payment } = \text{Firm's net receipt } \div \frac{95}{100}$$ or equivalently $$\text{Total payment } = \text{Firm's net receipt } \times \frac{100}{95}$$ and if you want the firm's net receipt to be $600$ then the total payment should be about $631.58$