Hello ….26 tuning forks are arranged in the order of increasing frequnecy ans any two successive forks give 2 beats when sounded together . If the frequency of the last fork is 4 times that of the first , find the frequency of the first fork .

As the successive forks produce a beat of 2 hertz , this means all the forks are in A.P. with common difference 2 hertz . Let us assume that frequency of 1st fork be F Hz. According to A.P. formula , frequency of last is (F+50) Hz. This is given as 4 times the first , so (F+50) = 4F F=(50/3) Hertz .