Question

the mean of 5 numbers is 30 if one number is excluded then it becomes 28 the excluded number is

Answer 1

Let total sum of 5 Numbers be x.

x / 5 = 30

x = 150

Now, one no. is removed.

Let removed no. be y.

150 - y / 4 = 28(here no. of observation become 4)

150 - y = 112

y = 38

So your answer is 38.

Answer 2

total sum =30×5=150

new mean = (150-x)/4
28=(150-x)/4
112=150-x
x=150-112
x=38