200 logs are stacked in the following manner 20 logs are in the bottom row,19 in the next row, 18 in the row next it to and so on. In how many rows 200 logs are place and how many logs are in the top row?
Answers
Answered by
4
Answer:
5
Step-by-step explanation:
20+19+17.....+5=200
Answered by
11
Answer:
n=16,an=5
Step-by-step explanation:
total logs=200
sn=200,an=?,a=20,d=-1
AP=20,19,18....
sn=n by 2[2a+(n-1)d]
200=n by 2[2(20)+(n-1)(-1)]
200*2=n[40+(n+1)]
400=n[41-n]
400=41n-nsquare
nsquare-41n+400=0
solve it
n=16 or n=25
solve it by formula-an=a+(n-1)d
an=5 or an=-4
n=4,an=5
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