Question

There are four unknown numbers. The mean of the first two numbers is 4 and mean
of the first three is 9. The mean of all four number is 15, if one of the four number is 2 find the other number ​

Answer 1

Step-by-step explanation:

let a, b, c, d be the unknown number.

gn

a+b/2=4

a+b=8(1)

a+b+c/3=9

a+b+c=27(2)

sub(1) in(2)

8+c=27

c=19

a+b+c+d/4=15

a+b+c+d=60(3)

sub(2)in(3)

27+d=60

d=33

a=2(from question)

sub a=2 in(1)

2+b=8

b=6

Answer:

a=2

b=6

c=19

d=33