If Rehana is currently 25 years old, she will be 25+5=<<25+5=30>>30 in five years.
Rehana will be three times as old as Phoebe in five years, meaning Phoebe will be 30/3=10 years old in five years.
Currently, Phoebe is 10-5=<<10-5=5>>5 years old.
3/5 of Phoebe's age now is 3/5*5=<<3/5*5=3>>3 years, which is Jacob's age.
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