Answer:
Step-by-step explanation:
Combine like terms
The present age of father is 86 years old and present age of son is 48 years old
<em><u>Solution:</u></em>
Given that, a father is now 38 years older than his son
Ten years ago he was twice as old as his son
Let "x" be the age of son now
Therefore, from given,
Father age now = 38 + age of son now
Father age now = 38 + x
<em><u>Ten years ago he was twice as old as his son</u></em>
Age of son ten years ago = age of son now - 10
Age of son ten years ago = x - 10
Age of father ten years ago = 38 + x - 10
Then we get,
Age of father ten years ago = twice the age of son ten years ago
38 + x - 10 = 2(x - 10)
28 + x = 2x - 20
2x - x = 28 + 20
x = 48
Thus son age now is 48 years old
Father age now = x + 38 = 48 + 38 = 86
Thus present age of father is 86 years old and present age of son is 48 years old
Answer:
99% confidence interval for the population average examination score is between a lower limit of 69.2872 and an upper limit of 82.7128.
Step-by-step explanation:
Confidence interval = mean +/- margin of error (E)
mean = 76
variance = 144
sd = sqrt(variance) = sqrt(144) = 12
n = 25
degree of freedom (df) = n - 1 = 25 - 1 = 24
confidence level (C) = 99% = 0.99
significance level = 1 - C = 1 - 0.99 = 0.01 = 1%
t-value corresponding to 24 df and 1% significance level is 2.797
E = t×sd/√n = 2.797×12/√25 = 6.7128
Lower limit = mean - E = 76 - 6.7128 = 69.2872
Upper limit = mean + E = 76 + 6.7128 = 82.7128
99% confidence interval is (69.2872, 82.7128)
X/6.2=-2.1
multiply both sides by 6.2
x=-13.02
Answer:
yor answer is 52
Step-by-step explanation:
