Answer:
Ravi's age after 15 years = x+15
Ravi's age = 4 times his present age = 4x
According to question -
15 + x = 4x
=> 15 = 4x-x = 3x
=> 15 = 3x
=> x = 15/3
=> x = 5
Thus , Ravi's present age is 5 years.
Step-by-step explanation:
Answer: 
Step-by-step explanation:
The confidence interval for population mean is given by :-

Given : Sample size : n= 35 , large sample (n>30)
Mean difference : 
Standard deviation : 
Significance level : 
Critical value : 
Now, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students will be :-

Hence, the 99.9% confidence interval for the mean difference between the marks scored last week and marks scored this week by all the students = 
Answer:
x = 3
Step-by-step explanation:
10x + 1 = 12x - 5
Subtract 1 from each side
10x = 12x - 6
Subtract 12x from each side
-2x = -6
Divided by -2
x = 3
The exception is if you are 60 days<span> late often which will certainly hurt your scores. Otherwise, one late payment should not cause long term damage. </span>90 days<span>late: This record will damage your credit scores significantly for up to </span>seven years<span>.</span>