Answer:
M = 3
Step-by-step explanation:
The first withdrawal takes place 1 - M/12 months until the end of the year. The second withdrawal takes place 2M/12 months before the end of the year.
$315,000 = ($300,000 x 1.16) - {$15,000 x [1 + 0.16(1 - M/12)]} - {$15,000 x [1 + 0.16(2M/12)]}
$315,000 = $348,000 - [$15,000 x (1.16 - 0.16M/12)] - [$15,000 x (1 + 0.32M/12)]
$315,000 = $348,000 - $17,400+ 200M - $15,000 - 400M
$315,000 = $315,600 - 200M
200M = $315,600 - $315,000 = $600
M = 600 / 200 = 3