Formula to find number of candies

[chullan88]

Hi,

Came across an interesting puzzle..
was trying to find solution via Excel...

You get three candies for 1$.And if you exchange three candy covers,you get an extra candy.
So how many candies will you get in total for a price of 45$?



Regards

[JohnTopley]

45$ buys 135 bars

trade the above at 3 wrappers per candy we get 45candies

trade again we get 15 candies

and again we get 5 candies

and again we get 1 candy + 2 spare wrappers

so we get a final 1 candy

=202


????

[chullan88]

Hi John,
Its the right answer!!
However I was thinking if its possible to get the answer with the help of a formula

[JohnTopley]

I am no mathematician ...

but we start with 5 and work "upwards" to 135 we have a geometric progression

=5* (1-3^4)/(1-3)

r=ratio : 3 in this case and 4 terms

this gives a result of 200

I don't know how you add the 1s (2 of them)!

[mahju]

You can use this formula in excel.

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Where J5 has dollars

Thanks

[chullan88]

You can use this formula in excel.

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Thanks

Great!!
Thank you so much