The Ski Shop received an invoice for $\$9600$ dated August 11, terms $5/10$, $2/30$, $n/90$, for the shipment of skis. The Ski Shop made two partial payments.
a) How much was paid on August 20th to reduce the unpaid balance to $\$7000$
b) How much was paid on September 10 to reduce the outstanding balance by $\$3000$
c) What is the remaining balance on September 10?
This questions is giving me troubles because I do not know how much money is in each partial payment.
The term $5/10$ means, that you have a reduction of $5\%$ of the required payment, if you pay within 10 days. Similar meaning of $2/30$. And $n/90$ means, that the invoice has to be fully paid after 90 days.
At a) the payment is within 10 days. You want to reduce the unpaid balance to $\$7000$. Therefore the reduction is $\$2600$. And you have to pay
$\$2600\cdot (100\%-5\%)=\$2600\cdot 95\%=\$2600\cdot 0.95=\$2470$
I think you can take it from here. If there are any questions, feel free to ask.