A pile of logs has 24 logs in the bottom layer, 23 in the second layer, 22 in the third, and so on. The top layer contains 10 logs. Find the total number of logs in the pile.
Can you please show the steps?
Can you please show the steps?
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a = 10
a_n = 24
d = 1
a_n = a + (n - 1)d
=> 24 = 10 + (n - 1)
=> n = 15
S_n = n/2 [2a + (n - 1) d ]
= 15/2 [20 + 14]
= 255
a_n = 24
d = 1
a_n = a + (n - 1)d
=> 24 = 10 + (n - 1)
=> n = 15
S_n = n/2 [2a + (n - 1) d ]
= 15/2 [20 + 14]
= 255
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when in doubt add em up. 255. (top+bottom)*(steps/2) 34*(15/2)
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24 + 23 + ... + 10
there are 15 terms
(10+24)*15/2 = 17*15 = 255
there are 15 terms
(10+24)*15/2 = 17*15 = 255
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