Question

Find the 16th term of the A.P. 7, 11, 15, 19…. Find the sum of the first 6 terms

Answer 1

I have uploaded the solution hope this helps you......

Answer 2

$\bf{\underline{Question:-}}$

Find the 16th term of the A.P. 7, 11, 15, 19…. Find the sum of the first 6 terms.

Given

• first term term (a) = 7
• Common difference (d) = 11 - 7 = 4

$\bf{\underline{Solution:-}}$

$\sf → a_{16} = ?$

Now,

$\large\bf{\red{ a_n = a+(n-1)d}}$

$\sf → a_{16}=7+(16-1)4$

$\sf → a_{16}=7+(15)4$

$\sf → a_{16}=7+60$

$\sf → a_{16} = 67$

• 16 term is 67

† Finding sum of 6th term †

$\bf\large{\red{S_n = \frac{n}{2}[2a+(n-1)d]}}$

$\sf → S_6 = \frac{6}{2}[2×7+(6-1)4$

$\sf → S_6 = 3[14 +(5)4]$

$\sf → S_6 = 3[14+20]$

$\sf → S_6 = 3[34]$

$\sf → S_6 = 102$