NIMCET 2017 — Reasoning PYQ

Given:
If all the statements are wrong
S say that I am certainly not over 40 year, means
S will be over 40 years
M says that I am 38 years and you are at least 5 years older than me, which means
M is not 38 years old, andalso S is not at least 5 years older than M
S says you are at least 39 years which means
M is not at least 39 year

Hence, the age of M and Scannot be determined.