SOLUTION: Please help me with this: Telephone poles are stored ina pile with 20 poles in the first layer, 19 in the second and so on. If there are 12 layers how many telephone poles does th

Question 326182: Please help me with this:
Telephone poles are stored ina pile with 20 poles in the first layer, 19 in the second and so on. If there are 12 layers how many telephone poles does the pile contain?
Found 2 solutions by scott8148, rfer:
Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
the 12th layer (11 layers above the 1st layer) has 20-11 or 9 poles in it

the 11th layer has 10 poles...and so on

the 1st layer plus the 12th layer is 29 poles ___ the 2nd layer plus the 11th layer is 29 poles ___ and so on

the total is ___ (1/2) * 12 * 29
Answer by rfer(16322) (Show Source): You can put this solution on YOUR website!
174
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