I have no idea how to start!

2) The mean of a set of six scores is 20
2a) What is the sum of these six scores?
2b) A seventh score is added and the mean of the seven scores is 22. What is the sum of the seven scores?
2c) What is the seventh score?

Question

I have no idea how to start!

2) The mean of a set of six scores is 20
2a) What is the sum of these six scores?
2b) A seventh score is added and the mean of the seven scores is 22. What is the sum of the seven scores?
2c) What is the seventh score?

jim_thompson5910 · Answer

Let S be the sum of the six scores

So the mean is equal to the sum (S) divided by the number of scores (6), which is 20, so

S/6 = 20

Solve for S

anonymous · Answer

S = 120?

jim_thompson5910 · Answer

good, that's the answer to 2a

jim_thompson5910 · Answer

in 2b, it becomes

(S+x)/7 = 22

(120+x)/7 = 22

Multiply both sides by 7 to find 120+x, which is the new sum

jim_thompson5910 · Answer

Then solve for x to find that 7th score

anonymous · Answer

Ok. I'll do that now

anonymous · Answer

34

jim_thompson5910 · Answer

you got it, the 7th score is 34

anonymous · Answer

Thanks so much @jim_thompson5910 !

jim_thompson5910 · Answer

yw