1.: At a certain flea maket, 35% of purchases are $10 to $20. The probablity that a consumer will be a male is 60%. What is the probablity that a consumer will be a female and will make a purchase between $10 and $20?
I think this is one of those "grid" exercises. So set up as:
grid:
$10 < x < $30?
yes no
+-----+-----+
male | | | 0.6
+-----+-----+
female | | | 0.4
+-----+-----+
0.35 0.65
The events would appear to be independent, so multiply to fill things in:
grid:
$10 < x < $30?
yes no
+------+------+
male | 0.21 | 0.39 | 0.6
+------+------+
female | 0.14 | 0.26 | 0.4
+------+------+
0.35 0.65
Then read the answer-value from the grid.
2.: Two sacks each contain 4 candies, 2 packs of gum, and 7 cookies. One item is randomly selected from each sack. What is the probablity that both selected items will be cookies?
What is the probability of drawing a cookie from one sack?
Since the sacks are independent, then what is the probability of drawing cookies from both sacks?
