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in an ap,the first term of an arithmetic series is 5,the last term is 45 and the sum is 400. find the number of terms and common difference​

Respuesta :

martin83po

Answer:

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Isha24

Answer:

Hi mate,

Step-by-step explanation:

Sn = n/2 (a+ l)

400 = n/2 ( 45 +5 )

400= N/ 2 (50)

400 = 25n

n =400/25 = 16

a n = a + ( n - 1 ) * d

45= 5 + (16-1) * d

45 = 5+ 15 d

40= 15 d

d = 40/ 15

=8/ 3

i HOPE IT IS CLEAR

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