Question

plzz solution plzzz​

Answer 1

Answer:

here is your answer

hope it helps

Answer 2

Explanation :

$\tt given \begin{cases} \sf{A. P :- 6, 13, 20 ........} \\ \sf{First \: term \: (a) = 6} \\ \sf{Common \: Difference \: (d) = 7} \end{cases}$

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$\tt To \: find \begin{cases} \sf{We \: have \: to \: find \: 12^{th} term} \\ \sf{Sum \: of \: 12 \: terms } \end{cases}$

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★ Solution :-

We know the formula to find A12.

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Formula is [An = a + (n - 1)d ]

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Where Number of terms (n) is 12.

A12 = 6 + (12 - 1)7

A12 = 6 + (11)7

A12 = 6 + 77

A12 = 83

∴ 12th term of the A. P is 83.

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Now,

We have to find the sum of 12 terms. So,

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Formula is [Sn = n(a + L) /2

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Where, n is 12 and L is 83.

S12 = 12(6 + 83)/2

S12 = 12(89)/2

S12 = 1068/2

S12 = 534

∴ Sum of first 12 terms of the A. P is 534