# Math Help - Balance after payments

1. ## Balance after payments

Contemporary Furnishing received an invoice on April 18 from Palliser furniture. the invoice for $18,976.45 was dated april 16 with terms 2/15, 1/30, n/45. a. What is the balance after a payment of$10,000 on May 1?
b. What additional payment on May 15 will settle the account?

By using this formula: N = L(1-d1) or this.. N = L(1-d1)(1-d2)

2. mm i'm not sure wheter my answer is correct or not..
for (a):
N= 18976.45 (1-0.02)
= $18596.92 balance : 18596.92 - 10000 =$8596.92

i don't know how to settle the question (b)..
can u give me the answer for this two question ??