Find the common difference d and the term a0 of the antithet

Find the common difference d and the term a_0 of the antithetic sequence whose 11th berm is 11 and 16th term is 10. The common difference d of the asthmatic sequence is The nth term, a_n of the arithmetic sequence is

Solution

a₁₁=a +10d=11

a₁₆=a+15d =10

subtracting both equations

5d=-1

d=-1/5

a+10d=11

a-2=11

a=13