Answer:
15 more weeks
Step-by-step explanation:
425 - 125 (what shes already saved)
300 divided by 20 (amount shes saving each week)
Result is 15, so 15 more weeks.
Hope this helped :)
If you mean how many weeks total, 125 according to the 20 dollars a week would bring it 22 weeks i think.. since the answer answer is 21.2 weeks exactly when you divide 425 by 20.
Answer:
a)P=0.42
b) 
Step-by-step explanation:
We have a binomial distribution, since the result of each experiment admits only two categories (success and failure) and the value of both possibilities is constant in all experiments. The probability of getting k successes in n trials is given by:

a) we have k=2, n=10 and p=0.01:

b) We have,
, Here P is the probability that at least one particle will penetrate the shield, this probabity has to be equal or greater than 0.95. Therefore, this will be equal to subtract from the total probability, the probability that the particles do not penetrate raised to the total number of particles.

Answer C is correct because 2×(4×305) is the same as (2×4)×305 and 2×4=8.