Math, asked by swathi302661, 1 year ago

the first term of an AP is 5; the last term is45 and the sum of all its terms is 400 find the number of terms and the common difference of the AP​

Answers

Answered by deve11
3

Step-by-step explanation:

a=5, an=45, Sn=400,n=?

Sn=n/2(a+an)

=> 400=n/2(5+45)

400*2/50=n

16=n.

Answered by veerendrakumaruppu
2
Given:

a = 5
an = 45
sn = 400

sn = (n/2)*(a + an)

400 = (n/2)*(5 + 45)

800 = n*50

n = 800/50 = 16

an = a + (n - 1)*d

45 = 5 + (16 - 1)*d

40 = 15 * d

d = 40/15 = 8/3

n = 16, d = 8/3 ——> Answer
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