Which nucleus would be least likely to undergo radioactive decay? A. A nucleus whose mass is equal to the sum of the masses of its
individual particles
B. A nucleus whose total mass is greater than the sum of the
masses of its individual particles
C. A nucleus with a mass that is less than the mass of an iron
nucleus
D. A nucleus whose total mass is less than the sum of the masses of
its individual particles

Answer
D
Explanation

Isso9

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.