Answer:
x=-5
Step-by-step explanation:

3x + 1y = ¹/₃ ⇒ 9x + 3y = 1
2x - 3y = 2²/₃ ⇒ 2x - 3y = 2²/₃
11x = 3²/₃
11 11
x = ¹/₃
3x + y = ¹/₃
3(¹/₃) + y = ¹/₃
1 + y = ¹/₃
- 1 - 1
y = ⁻²/₃
(x, y) = (¹/₃, ⁻²/₃)
Answer:
a) -1.25
b) 0.2112
c) -1.96
Step-by-step explanation:
Data provided in the question:
Sample size, n = 400
H0 : p = 20
= 175
Now,
a) The test statistic is given as:
Z = 
on substituting the respective values, we get
Z = 
= -1.25
b) The p-value = 2 × P(Z <-1.25)
Now from the standard normal table
P(Z <-1.25) = 10.56% = 0.1056
Thus,
p-value = 2 × 1056 = 0.2112
c) for a = 0.05,
the critical value is
i.e 
Now from standard normal table
= -1.96