Question

what is the difference between 60th and 30th terms in arithmetic sequence 5, 8, 11​

Answer 1

Answer:

$5 \: 8 \: 11 \\ a = 5 \\ d = 8 - 5 \\ = 3 \\ \\ t{n} = a + (n - 1)d \\ \: t{60} = 5 + (60 - 1)3 \\ = 5 + 59 \times 3 \\ = 5 + 177 \\ t60 = 183 \\ \\ t{30} = 5 + (30 - 1)3 \\ = 5 + 29 \times 3 \\ = 5 + 87 \\ t30 = 93 \\ \\ \\ difference \: between \: t60 \: and \: t30 = t60 - t30 \\ = 183 - 93 \\ = 90$

Answer 2

In the given A.P :-

• First term = a = 5
• Common difference = d = 8 - 5 = 3

To find:

Difference between 60th term and 30th term

Solution :-

For finding the 60th term:

aₙ = a + (n - 1)d

→ a₆₀ = 5 + (60 - 1) 3

→ a₆₀ = 5 + 59(3)

→ a₆₀ = 5 + 177

→ a₆₀ = 182

For finding the 30th term:

aₙ = a + (n - 1)d

→ a₃₀ = 5 + (30 - 1)3

→ a₃₀ = 5 + 29(3)

→ a₃₀ = 5 + 87

→ a₃₀ = 92

Difference between 60th and 30th term:

= 182 - 92

= 90

∴ The difference between 60th and 30th term is 90.