A is 4 year older than B ->A=B+4.......1
who s twice as old as C ->B=2C........2
Total of the ages of A, B and C is 44-> A+B+C=44------------3
substitute A,B value
B+4+2C+C=44
B+3C=40...........4
take 2nd and 4th equation
B+3C=40
B-2C=0
C= 8
A=20,B=16,C=8
product of their ages ->A*B*C=2560