The sequence 59,A1,A2,…,A39,159 forms an arithmetic progression with 41 terms.
The common difference d is given by d=39+1159−59=40100=2.5
The k-th arithmetic mean is Ak=59+k⋅d
The required mean is 4A25+A28+A31+A36
4A25+A28+A31+A36=4(59+25d)+(59+28d)+(59+31d)+(59+36d)
=44×59+120d=59+30d
Substituting d=2.5:
=59+30(2.5)=59+75=134
Answer: 134