Before going into the details of the problem, let us first write down the most important information required for solving this problem.
1 ft = 12 inches
The distance that was crawled by Jack = 4 ft
= (4 * 12) inches
= 48 inches
The distance crawled by Christine = 3/4 of the distance crawled by Jack
= (3/4) * 48 inches
= 3 * 12 inches
= 36 inches
Then
The total distance crawled by the two children's = (48 + 36) inches
= 84 inches
So Jack and Christine together crawled a distance of 84 inches.
90 I’m sorry if I am wrong I got that in paper :)
69.5 percent of 85 is 59.075
The z-score is given by:
z=(x-μ)/σ
but
x-μ=52
thus
z=52/√84681
z=0.1787
Thus:
P(X≤52)=0.9633
