672×36×25=604800 Checking option (a) Number of seconds in 5 days =5×24×60×60= 432000 Checking option (b) Number of seconds in 1 week =7×24×60×60=604800 Checking option (c) Number of minutes in 7 weeks =7×7×24×60=70560 Checking option d) Number of hrs. in 60 days =60×24=1440 Hence, answer is (b)