Please help. I don't understand how to solve for number 17, 19, and 21. Please show how you solved each problem

(17) From the plot, you see that

Pr[$15,500 ≤ x ≤ $18,500] = 99.7%

We can split up the probability on the left at the mean, so that

Pr[$15,500 ≤ x ≤ $17,000] + Pr[$17,000 ≤ x ≤ $18,500] = 99.7%

Any normal distribution is symmetric about its mean, so the two probabilities here are the same. The one on the left is what you want to compute. So you have

2 × Pr[$15,500 ≤ x ≤ $17,000] = 99.7%

==>   Pr[$15,500 ≤ x ≤ $17,000] = 49.85%

(19) The mean of a normal distribution is also the median, so half the distribution lies to either side of the mean. Mathematically, we write

Pr[x ≥ $17,000] = 50%

The plot shows that

Pr[$16,500 ≤ x ≤ $17,500] = 68%

and by using the same reasoning as in (17), we have

Pr[$16,500 ≤ x ≤ $17,000] + Pr[$17,000 ≤ x ≤ $17,500] = 68%

2 × Pr[$17,000 ≤ x ≤ $17,500] = 68%

Pr[$17,000 ≤ x ≤ $17,500] = 34%

Now

Pr[x ≥ $17,000] = 50%

Pr[$17,000 ≤ x ≤ $17,500] + Pr[x ≥ $17,500] = 50%

34% + Pr[x ≥ $17,500] = 50%

==>   Pr[x ≥ $17,500] = 16%

(21) From the plot,

Pr[$16,000 ≤ x ≤ $18,000] = 95%

This means (by definition of complement) that

Pr[x ≤ $16,000 or x ≥ $18,000] = 100% - 95% = 5%

and by symmetry,

Pr[x ≤ $16,000 or x ≥ $18,000] = 5%

Pr[x ≤ $16,000] + Pr[x ≥ $18,000] = 5%

2 × Pr[x ≤ $16,000] = 5%

==>   Pr[x ≤ $16,000] = 2.5%

answer: the 4 kilogram bag

step-by-step explanation: this is because if you divide the number of kilograms into the total it will tell you how much each individual kilogram would be worth. 2 kilos is 7 and change 3 would be around 6 ish and the 4 kilo would be 4.6 and change and the 5 kilos would be like 4.88