Answer:
27 days.
Step-by-step explanation:
Find 1% out of the 30-day period.
100% = 30 days
1% = 30 ÷ 100 = 0.30
Now find the percentage reported that had measurable snowfall which is 90%.
90% = 0.30 x 90 = 27
Out of the 30-day period, only 27 days received measurable snow.