Answer: a) Required minimum sample size= 219
b) Required minimum sample size= 271
Step-by-step explanation:
As per given , we have
Margin of error : E= 5% =0.05
Critical z-value for 90% confidence interval : 
a) Prior estimate of true proportion: p=28%=0.28
Formula to find the sample size :-

Required minimum sample size= 219
b) If no estimate of true proportion is given , then we assume p= 0.5
Formula to find the sample size :-

Required minimum sample size= 271
Answer:x>7 or x ≤ -3
Solving the 1st inequality
-6x +14 < -28 --------------- (Collect like terms)
-6x < -28 - 14
-6x < - 42 -------------------- (Divide both sides by -6)
Note: If you decide an inequality expression by a negative value, the inequality sign changes)
-6x/-6 > -42/-6
x > 7
Solving the 2nd inequality
9x + 15 ≤ −12 ----------- (Collect like terms)
9x ≤ −12 - 15
9x ≤ −27 ------------------(Divide both sides by 9)
9
9x/9 ≤ −27/9
x ≤ -3
Bring both results together, we get
x>7 or x ≤ -3
The final result is complex (i.e. can't be combined together).
Step-by-step explanation:
gina saved $14
convert your percentage into a decimal: 20% converts to 0.20
then, just multiply 0.20 with 70. you should get 14.