I have a formula challenge

Hi,
If N=Number of bits then

N*(N+1)/2 * 500/100 = Number of hours

In your example: 4 *(4+1)/2 *500/100= 50 hours

Or more generally

N*(N+1)/2* Footage per bit/Removal rate per hour

So if a1=N, B1=Footage per bit, c1=Removal rate per hour then Hours (say) in
D1

= A1*(A1+1)/2*(B1/C1)



"mgmcdevitt" wrote:

>
> I need a formula for excel that can do the following:
>
> I am from a drilling company and we have to price drill bit
> replacements into your bids. The number of feet before the bit needs to
> be replaced will be given. Then from the total depth drilled we
> calculate the number of bits needed and round that number up.
>
> I need to calculate the number of hours required to remove the drill
> bits after each of them is unusable.
>
> For example: Total footage to drill 2000’; bit footage before
> replacement 500’, which is 4 bits. I am assuming it takes 100ft/hr to
> remove the drill pipe with the drill bit.
>
> Bit Depth Hrs
> 1 500 5
> 2 1000 10
> 3 1500 15
> 4 2000 20
> Totals Hrs = 50
>
> How do I use an excel formula to calculate total hours required to
> remove all of the bits with just the 100ft/hr, # of bits, and footage
> before bit replacement?
>
>
> --
> mgmcdevitt
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