Math, asked by rajnaaz, 1 year ago

In an AP the first term is-5 and last term is 45. If sum of all number in the AP is 120,. how many terms are there?what is the common difference?

Answers

Answered by rajasekarvenkatesan

Answer:

Step-by-step explanation:

a = -5

a + (n-1)d = 45

Sn = n[a + an]/2

120 = n[40]/2

240 = 40n

n = 6

rajnaaz: ty

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rajnaaz: ok

Answered by yashwanthSN0247

Answer:6
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