Find the 10th and 26th terms of the AP: 3, 8, 13, 18, ...... Class 9

Find the 10^th and 26^th terms of the AP: 3, 8, 13, 18, ...... Class 9

Question 1.

Find the 10^th and 26^th terms of the AP: 3, 8, 13, 18, ...... Class 9

Solution:

The given AP is 3, 8,13, 18, ...

a = 3, d = 8 - 3 = 5

t_n = a + (n - 1) d

For n = 10,

t₁₀ = 3 + (10 - 1) × 5

∴ t₁₀ = 3 + 9 × 5

∴ t₁₀ = 3 + 45 = 48

For n = 26,

∴ t₂₆ = 3 + (26 - 1) × 5

∴ t₂₆ = 3 + 25 × 5

∴ t₂₆ = 3 + 125 = 128

∴ 10^th and 26^th term of the AP is 48 and 128, respectively.