Please write out the explanation and the formula so i can see the steps, thank you

Firm X is being acquired by Firm Y for $35,000 worth of Firm Y stock (valued at the pre-merger current price of Y). Both firms are "all-equity" financed. The incremental value created by the merger is $2,500. Firm X has 2,000 shares of stock outstanding at $16 per share. Firm Y has 1,200 shares of stock outstanding at a price of $40 per share. What is the actual cost of the acquisition to Firm Y using company stock? Why is the actual cost less than $35,000?