(a) Average time to get to school
Average time (minutes) = Summation of the two means = mean time to walk to bus stop + mean time for the bust to get to school = 8+20 = 28 minutes
(b) Standard deviation of the whole trip to school
Standard deviation for the whole trip = Sqrt (Summation of variances)
Variance = Standard deviation ^2
Therefore,
Standard deviation for the whole trip = Sqrt (2^2+4^2) = Sqrt (20) = 4.47 minutes
(c) Probability that it will take more than 30 minutes to get to school
P(x>30) = 1-P(x=30)
Z(x=30) = (mean-30)/SD = (28-30)/4.47 ≈ -0.45
Now, P(x=30) = P(Z=-0.45) = 0.3264
Therefore,
P(X>30) = 1-P(X=30) = 1-0.3264 = 0.6736 = 67.36%
With actual average time to walk to the bus stop being 10 minutes;
(d) Average time to get to school
Actual average time to get to school = 10+20 = 30 minutes
(e) Standard deviation to get to school
Actual standard deviation = Previous standard deviation = 4.47 minutes. This is due to the fact that there are no changes with individual standard deviations.
(f) Probability that it will take more than 30 minutes to get to school
Z(x=30) = (mean - 30)/Sd = (30-30)/4.47 = 0/4.47 = 0
From Z table, P(x=30) = 0.5
And therefore, P(x>30) = 1- P(X=30) = 1- P(Z=0.0) = 1-0.5 = 0.5 = 50%
The answer is 11
Explaination:
9/14 multiple both numbers by 3=27/42
Break 2 1/3 into 2 and 1/3
1/3 multiple both numbers but 14=14/42
27/42 x 14/42 keep number on the bottom the same
27x14= 378
Divide 378/42=9
Add the 2 from 2 1/3 to the nine
2+9=11
The hydronium ion is H₃O⁺ and its concentration is equivalent to the H⁺ ion concentration. The H⁺ ion concentration is given by:
pH = -log[H⁺]
[H⁺] = 10^(-8.2)
[H⁺] = 6.31 x 10⁻⁹ mole/dm³
The hydronium ion concentration is 6.31 x 10⁻⁹ mole/dm³
You could simplify 255
100+100+55
for each hundred there's 15$ earned so 15×2 =30$
there's 55 left and 1 till 99 =0.10 each
55×0.10=5.5$
30+5.5=35.5
in short the answer is 35.5$
