Question

Frustrated. Hopefully someone can help. Infinite geometric series attachment below.

Answer 1

.15 [With a bar over 15] Means:

0.15151515151515151515 ..... till forever.

Which of the following options do you think will sum up to .15 bar ?

Answer 2

I'm thinking B.

Answer 3

@AkashdeepDeb

Answer 4

Can you explain why B? :D

Answer 5

Because the other ones have zeroes before and after it... B only has the .15 one and I'm assuming that .15 means that it will go .15151515151515 for infinity and beyond?

Answer 6

Good guess but the logic is a little bit different here.

In a geometric series, if you add .15 up till infiniti.


You'll get

.15 + .15 + 15 + .15 +15 + .15 +15 + .15 .... = More than some finite value!

Here we want to get 0.15151515151515151515151515.....

So essentially, we'd want to add up something like

0.15 + 0.0015 + 0.000015 .... = Which gives us 0.15 15 15 ..... [till infiniti]

Did you understand why this is the case? :)

Answer 7

Ohhhh yeah because you have to put 15 over 100 and then 10,000 and 1,000,000 and so on.

Answer 8

So that would mean that I get C, I believe.

Answer 9

@AkashdeepDeb

Answer 10

Great work! You got it. :D

Answer 11

Thanks for your help!

Answer 12

:)