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Venmo charges business transaction fee of .10 and 1.9%. Let's say I want to know how much to charge to ensure I get an accurate and specific take after Venmo's fees. What would the formula be?

Right now, it's a matter of brute force; I guesstimate and do the math. But as you add money to offset, the percentage Venmo takes increases. That's why I can't figure out how to do this accurately from an input of my desired take without brute force. Forgive me if I'm missing something obvious.

Alicia
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1 Answers1

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If I understand your question correctly, Venmo takes $\$0.10$ plus $1.9\%$ of every transaction. We want to make $\$d$ from a transaction, the amount of which is $\$t$. Venmo will take

\begin{equation*} \$0.10 + 0.019t \end{equation*}

as a fee, and so in order to make $\$d$ from the transaction, we need the transaction amount to satisfy

\begin{equation*} \$ t - (\$0.10 + 0.019t) = \$d\implies \$t = \frac{\$d + \$0.10}{0.981}. \end{equation*}

kandb
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  • This is not right. For example, if $d=100$ then your formula gives 102. But if I charge 102, then Venmo takes 102*0.019 + 0.1 = 2.038 which is more than the 2 dollars I wanted them to take. – Ted Jan 20 '23 at 05:38
  • @Ted, yes, I was quite wrong! Thanks for pointing that out. I think the solution should now be OK. – kandb Jan 20 '23 at 05:45
  • $0.01 should be $0.10 in the new solution, but otherwise looks right. – Ted Jan 20 '23 at 17:40