Question

if the mean of the observations: x,x+3,x+5,x+7x+10 is 9, then find the mean of the last three observations.

Answer 1

ᴍᴇᴀɴ = sᴜᴍ ᴏғ ᴀʟʟ ᴏʙsᴇʀᴠᴀᴛɪᴏɴ/ɴᴏ: ᴏғ ᴏʙsᴇʀᴠᴀᴛɪᴏɴs

ᴍᴇᴀɴ = x+x+3+x+5+x+7+x+10/5

ᴍᴇᴀɴ = 5x+ 25/5

ᴍᴇᴀɴ = 5(x+5)/5------(5 ɪɴ ɴᴜᴍᴇʀᴀᴛᴏʀ ᴀɴᴅ ᴅᴇɴᴏᴍɪɴᴀᴛᴏʀ ɢᴇᴛs ᴄᴀɴᴄᴇʟʟᴇᴅ)

ᴍᴇᴀɴ =x+5

(ᴍᴇᴀɴ =9)-------》ɢɪᴠᴇɴ

9= x+5

9-5=x

4 = x

ᴛʜᴇ ᴛᴇʀᴍs ᴀʀᴇ:

4,7,9,11,14

ᴛʜᴇ ʟᴀsᴛ ᴛʜʀᴇᴇ ᴛᴇʀᴍs ᴀʀᴇ 14,11,9

ᴍᴇᴀɴ = sᴜᴍ ᴏғ ᴀʟʟ ᴏʙsᴇʀᴠᴀᴛɪᴏɴ/ɴᴏ: ᴏғ ᴏʙsᴇʀᴠᴀᴛɪᴏɴs

ᴍᴇᴀɴ = 14+11+9/3

ᴍᴇᴀɴ = 34/3 = 11.33

_______❤FOLLOW ME❤______

.......................... ^_^.............................