Answer:
0.0158 = 1.58% probability that all of them are under 18.
Step-by-step explanation:
Probability of independent events:
If three events, A, B and C are independent, the probability of all happening is the multiplication of the probabilities of each happening, that is:

The percentage of people under the age of 18 was 23.5% in New York City, 25.8% in Chicago, and 26% in Los Angeles.
This means that 
If one person is selected from each city, what is the probability that all of them are under 18?
Since the three people are independent:

0.0158 = 1.58% probability that all of them are under 18.
Answer:
Its really simple look it up at some site
Based on the numbers we have we can assume that she saves 3 times more each week than the last (1*3=3, 3*3=9).
Following this trend we would multiply the amount she saved the third week ($9) by 3 to get $27 for the fourth week.
Then, we would multiply the amount she saved the fourth week ($27) by 3 to get $81 for the fifth week.
Finally, to figure out how much she saved in the 5 weeks, we need to add each value up to get 1+3+9+27+81= $121 saved in 5 weeks