5, 8, 6 and k occur with frequency 3, 2, 4, and 1 respectively and have a mean of 5.7. Find the value of k?
A
4
B
3
C
2
D
1
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
x
f
fx
5
3
15
8
2
16
6
4
24
k
i
k
∑f=10
∑fx=55+k
Mean = \(\frac{∑fx}{∑f}\)
5.7 = \(\frac{55 + k}{10}\)
57 = 55 + k
k = 57 - 55
k = 2
Source: Myschool Past Questions Archive (Record #9390)