Question

11. If first second last and last
term of AP are -6,26and
30.Then find the number of
terms.​

Answer 1

Answer:

10 terms.

Step-by-step explanation:

Given: t1 = -6 t (n-1) = 26 tn = 30

To find: Number of terms (n) = ?

Solⁿ:

here, common difference (d) = tn - t (n-1)

= 30 - 26

d = 4

Therefore,

as per formula, tn = a + (n -1) d

where, a = t1

Therefore,

30 = (-6) + (n - 1) 4

30 = (-6) + 4n - 4

30 = -10 + 4n

40 = 4n

n = 10

Hence, the A.P. will have 10 terms.

Hope it helps you

PLEASE Mark as BRAINLIEST

Answer 2

Answer:

$\huge\mathfrak\green{Hey\ friend\ your\ answer\ is ...............}$

There are 10 terms in the series.

Step by step explanation:

Given :

1st term = -6 => a = -6

2nd last term = 26

last term = 30 => l (t n)= 30

d = t n - t n-1

d= 30 - 26 = 4

Formula to be used :

$\huge{\boxed{l = a + (n-1)d}}$

=> 30 = -6 + (n-1) × 4

=> 30 + 6 = (n-1) × 4

=> $\frac {<em>3</em><em>6</em>}{<em>4</em>} <em>=</em><em> </em><em>n</em><em>-</em><em>1</em><em> </em>$

=> 9 = n-1

=> 9 + 1 = n

$\therefore n = 10$

$\huge{\boxed{\boxed{No.of\ terms = 10 }}}$

$<marquee>$

Hope it helps u ..........

: )