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the first term of an arithmetic sequence is 5, the last term is 45 and the sum is 275. how many terms are there?

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AGboiiviz

[tex]\large\underline{ \mathcal {SOLUTION}}:[/tex]

Sn = n(A1+An)/2

275 = n(5+45)/2

275 = n(50)/2

275×2 = n(50)

550 = 50n

550/50 = n

11 = n

[tex] \\ [/tex]

[tex]\large\underline{ \mathcal {ANSWER}}:[/tex]

  • There are 11 terms