To answer the question above, Let n be the no. of sold wallet 1 wallet = $12 yesterday = n today = n - 3 over the past two days = $396
an equation that models the situation: n x $12 + (n - 3) x $12 = $396 n x 12 + (n - 3) x 12 = 396 n x 12 + n x 12 - 3 * 12 = 396 2 x n x 12 - 36 = 396 n x 24 = 396 + 36 n x 24 = 432 n = 432 / 24
The answer is Shannon sold n = 18 wallets yesterday.
