Answer: C) 133
Step-by-step explanation:
The formula to find the sample size is given by :-

, where z* = Critical z-value
= Population standard deviation for prior study.
E= Margin of error.
As per given , we have
E= 5
The critical z-value for 90% confidence level is 1.645.
Substitute al;l the value sin the above formula , we get




Hence, the minimum sample size needed is 133.
Thus , the correct answer is : C) 133
B
I need 20 characters lol
Ok the ladder and the ground will make a right triangle/right angle. This is because the ground is flat, the wall is straight and only the ladder is leaning/slanted. I hope this helps.
29 = 160 - x
x = ?
160 - 29 = 131
SO x = 131
Check:-
160 - 131 = 29
SO,
29 = 160 - 131.
Hope i helped ya!