First lets write down our starting conditions:
we have 22 gallons and it has 16% of ammonia
16% of 22 gallons is
A = 16/100*22 = 3,52 gallons
Now since only watter is evaporating that means that in second scenario after some watter evaporated there is still 3,52 gallons of ammonia. But now those 3,52 gallons of ammonia represent 24% of total mixture. So now we go other way.
24 % is 3,52 gallons
100% is x gallons
x = 100/24*3,52 = 14.667 gallons
That means that he has to evaporate
22 - 14.6667 = 7,333 gallons of water.
Answer:
The standard deviation of car age is 2.17 years.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 7.5
(a) If 99.7% of the ages are between 1 year and 14 years, what is the standard deviation of car age?
This means that 1 is 3 standard deviations below the mean and 14 is 3 standard deviations above the mean.
So

I want to find 



The standard deviation of car age is 2.17 years.
Answer:
Step-by-step explanation:
Let x represent the number of toys that each club member donated.
There are 9 students in a service club.
If each club member donated 4 children's books for the baskets, it means that the total number of books donated by the club members would be
9 × 4 = 36
If each club member also donated an equal number of toys. It means that the total number of toys donated by the club members would be
9 × x = 9x
A total of 63 items were collected for the baskets. Therefore, the linear equation that you can use to find how many toys each club member donated would be
9x + 36 = 63
Answer: 5.75
Step-by-step explanation:
3/4=.75 then add the 5