Question

Which term of the AP : 3,8,13,18,...is 78?

Answer 1

${\huge{\pink{↬}}} \: \: {\huge{\underline{\boxed{\bf{\pink{Answer}}}}}}$

• 16th term
• The given arithmetic progression is 3, 8, 13, 18,
• Answer: 78 is the 16th term of AP.

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Answer 2

Given :

• a = 3
• d = 8-3 = 5
• an = 78

Solution :

→ an = a + (n-1) d

→ 78 = 3 + (n-1) 5

→ 78 - 3 = (n-1) 5

→ $\frac{75}{5}$ = (n-1)

→ 15 + 1 = n

• → n = 16