Question about summation Notation

Hi,

I have a reading problem that I need some help with. I'm not sure how to figure the summation notation part of it. My instructor said we could use a calculator but I don't even know how to put that part into a calculator. Here is my question.

[FONT=&quot]1. [/FONT][FONT=&quot]Figure below shows the layout of an office building. If the distance between the AP and the mobile stations (MSs)1, 2 and 3 are 40 , 60, and 20 meters, respectively determine the path loss for between the AP and MSs by using a loss of 4dB per wall. Use the given (below) specification of 802.11 power (transmit and receive) to determine whether a single AP can cover the entire building. L_p is the maximum allowable path loss between AP and terminal, d is the distance in meter from AP to terminal, m_type is the number of walls between AP and terminal, W_type is loss in dB per wall and L₀ is a constant value of 40.5 dB. dBm.[/FONT]

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[FONT=&quot] [/FONT][FONT=&quot]802.11 power transmission is +20dBm while the minimum receiver sensitivity is -75 dBm.[/FONT]



Here is what I have so far

Path Loss = 40.05 + 20log(40)+(summation Notation)*8

If you could help me on figuring out the summation notation part of the problem I think I could do the rest.

Thanks,
Sunwers