Let the amount she has on Thursday morning be x.
By thursday afternoon, she has (0.87)x
By close, she has (0.87)x + 1633.09.
Since by close, she has 316.84 more, we will get:
(0.87)x + 1633.09 = x + 316.84
x - (0.87)x = 1633.09 - 316.84
0.13x = 1316.25
x = 1316.25 / 0.13
x = 10125
Hence, she has 10125 shares on Thursday morning.