ARITHMETIC PROGRESSION - 5

The 1st term of an A.P. is 70 and the common difference is 20. Find the 10th term.

Solution

A₁= 70, d = 20

A_n = A₁ + (n-1)d

A₁₀ = A₁ + (10-1)d

A₁₀ = A₁ + 9d

A₁₀ = 70 + (9x20) [ after substituting A₁= 70, d = 20 as given above]

∴ A₁₀ = 70 + 180

A₁₀ = 250

Hence the 10th term is 250.

TRY THIS……………

The 1st term of an A.P. is 30 and the common difference is 43. Find the 7th term.