Statisticshard · Past Paper
If the mean of $a, b$ is 10, and $b, c$ is 20, then $c-a$ is:
A10
B20
C30
D40
✓ Correct Answer: B — 20
$a+b = 20$, $b+c = 40$. Subtracting the first from the second gives $c-a = 20$.
Share this question
More from Statistics
- Find the median of the following frequency distribution: x=5, 10, 15, 20 with f=3, 7, 6, 4.
- In a distribution, if all observations are increased by $k$, the median:
- In a lottery, there are 5 prizes and 20 blanks. What is the probability of not winning a prize?
- If the frequencies of classes 0-10, 10-20, 20-30 are 5, 8, 7, what is the 'more-than' cumulative frequency for class 10?
- An urn contains 4 red, 5 blue and 6 green balls. Three balls are drawn at random. What is the probability that all are of different colors?