Ex9-2 The length of a survey line was measured with a tape having nominal length 20 m and was found to be 236.4 meter. As a check the length was again measured with a 30 m tape and was found to 240.5 meter. On testing, it was found that the 20 meter tape is 6 cm too short. Estimate the true length of 30 m tape.
Solution : Given , 20m tape is 6 cm too short
Thus, from
