Answer:
Explanation:
Let Bettina's age be B.
Then Darren's age is 3 times Bettina's, or 3B.
Jonathan's age is twice that of Darren, i.e. 2 (3B) = 6B.
Altogether, the sum of their age is
B + 3B + 6B = 120 years
10 B = 120 years
B = 12 years.
Therefore
Bettina is 12 years old
Darren is 3 times as old as Bettina, so 36 years old.
Jonathan is twice that of Darren, so 72 years old.
Total = 72+36+12= 120 years, check! :)