The amount of shares that Stam should use to calculate basic earnings per share is 360,000 share.
Basic earnings per share
Shares outstanding at the beginning of the year      200,000 shares
Add additional shares issued                      40,000 shares
Total shares outstanding                          240,000 shares
(200,000+40,000)
Add 50% stock dividend distributed                120,000 shares
(50% x 240,000)
Basic earning per share                          360,000 shares
(240,000+120,000)
Inconclusion the amount of shares that Stam should use to calculate basic earnings per share is 360,000 share.
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