Answer:
3. 1/28
4. About 7.11%
Explanation:
3.
Since two of the eight ads are by a local retailer, the probability of picking either one once is 2/8=1/4. However, the second time, since on of the ads has already been used and there are a total of 7 left, the new probability is 1/7. Multiplying these two together, you get 1/4*1/7=1/28.
4.
To find the probability, you need to find the area of the smaller triangle and the rest. The formula for the area of an equilateral triangle is
, meaning that the area of the big triangle is
and the area of the little triangle is
.
. Hope this helps!