Answer:
0.97547
Step-by-step explanation:
Given That:
Mean (m) = 102
Standard deviation (σ) = 12
Sample size (n) = 63
Probability that sample mean would differ from Population mean by less than 3.4 watts
P(m - s < X < m + s)
P(102 - 3.4 < Z < 102 + 3.4)
Using the Z formula :
Zscore = (x - m) / (σ/√n)
x = 102 - 3.4 = 98.6 ; x = 102 + 3.4 = 105.4
Z = (98.6 - 102) / (12/√63) = −2.248888
P(Z < - 2.2488) = 0.012263 (Z probability calculator)
Z = (105.4 - 102) / (12/√63) = 2.2488886
P(Z < 2.2488) = 0.98774 (Z probability calculator)
0.98774 - 0.012263 = 0.97547
Combined like terms than subtract with system of equations
Answer:
The approximate time that it will take Mary to save R40000 is 29 years
Step-by-step explanation:
A= p(1+r/n)^nt
t = log(A/P) / n[log(1 + r/n)]
A = R40000
n = 4
P = R400
r = 16%
t = log(A/P) / n[log(1 + r/n)]
= log(40,000 / 400) / 4{log(1+0.16/4)}
= log(100) / 4{log(1+0.04)}
= 2 / 4{log(1.04)}
= 2 / 4(0.0170)
= 2 / 0.068
= 29.41
t = 29.41 years
Approximately 29 years
The approximate time that it will take Mary to save R40000 is 29 years
