According to the description in the SRD, you'd think that it's (1.5*1d6)+5 (since only 1d6 is a variable numeric effect, but the PHB clarifies this with a magic missile example (for each missile, roll 1d4 +1, and then multiply the total result by 1.5. So, go with 1.5*(1d6+5)
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wow three posts...