Question

Find the 11th term from the last term ( towards the first term ) of the A.P: 10,7,4,..,-62.

Answer 1

→Question: Find the 11th term from the last term ( towards the first term ) of the A.P: 10,7,4,..,-62.

→Solution:

↔Here,

• a = 10
• d = 7-10 = -3
• l = -62

⇔We know:

• l = a+(n-1)d
• So, substitute the values:
• -62 = 10+(n-1)(-3)
• -72 = (n-1)(-3)
• n - 1 = 24
• n = 25

∴There are 25 terms in the given A.P

⇒But we want the 11th term:

• 11th from last term = (25 - 10)th term
• 15th term

⇔Applying the formula:

• a of nth term = a + (n-1) d
• 10+(15-1)(-3) = 10 -42 = -32

∴The 11th term from the last term will be -32

Answer 2

Here,

a = 10

d = 7-10 = -3

l = -62

⇔We know:

l = a+(n-1)d

So, substitute the values:

-62 = 10+(n-1)(-3)

-72 = (n-1)(-3)

n - 1 = 24

n = 25

∴There are 25 terms in the given A.P

⇒But we want the 11th term:

11th from last term = (25 - 10)th term

15th term

⇔Applying the formula:

a of nth term = a + (n-1) d

10+(15-1)(-3) = 10 -42 = -32

∴The 11th term from the last term will be -32