Answer:
-4r - 11 = 4r + 21
-4r -4r = 21 + 11
-8 = 32 (Divide both sides by -8)
/ /
-8 -8
= -4
Step 1: Distributive Property
Step 2: Subtraction Property of Equality
Step 3: Addition Property of Equality
Step 4: Division Property of Equality
Answer:
A sample of 997 is needed.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
In which
z is the z-score that has a p-value of
.
The margin of error is of:

A previous study indicates that the proportion of left-handed golfers is 8%.
This means that 
98% confidence level
So
, z is the value of Z that has a p-value of
, so
.
How large a sample is needed in order to be 98% confident that the sample proportion will not differ from the true proportion by more than 2%?
This is n for which M = 0.02. So






Rounding up:
A sample of 997 is needed.
Adults = 9
Children = 2
Let x be the number of adults.
11-x is the number of children.
22x + 15(11-x) = 228
22x + 165 - 15x = 228
22x - 15x = 228 - 165
7x = 63
7x / 7 = 63 / 7
x = 9 number of adults.
11 - x = 11 - 9 = 2 number of children.
To check:
22x + 15(11-x) = 228
22(9) + 15(11-9) = 228
198 + 30 = 228
228 = 228
(not my answer btw)