Challenging data interpretation PowerPrep problem! help :)

[e_yas7]

Hello guys!
I am really stuck with this one!
help! can anyone find a solution to this DI problem

SPOILER: answer: 270,000

[e.cartman]

Looking roughly at the interval between Jan 71 and jan 72, you should be able to guesstimate the average as around 22,000. Multiply that by 12 to get answer 264,000. Closest to 270k.

But I would love to know if there is a more rigorous or systematic approach.

[chestnut.cc]

There are actually little notches on the graph... so if you have the patience... you can count a few representative deviations from a fixed value... for eg 20,000... and add that to the total of 12*20000... approx 4,3,3,2,2,1,2,2... mean approx 2... so the ans works out like in cartmans case to be 260,000... E

[Goldust]

I agree with e.cartman, although I took the average to be 23,000.

[e_yas7]

thanks guys!
at first, i went with the bruteforce described by chestnut.cc, but i think we should guesstimate as e.cartman suggested.

any other approach is welcome!

[grexam]

yea exactly........what I did was in the begining it was clode to 24000 so gradual decrease to 21000 and then rose to 2200 in Jan 72

so overall this was what I estimated
24000 =3months apprx
21000=3months apprx
22000=6months apprx (since it lowered from 24k to 21k and again 21k to22k)

so 24000*3+21000*3+22000*6=267000

so E is the answer

any suggestion please do tell if wrong

Thanks