The word(s) "useful" appears 3 time(s) in 3 verse(s) in Quran in Muhammad Pickthal translation.

(1) They question thee about strong drink and games of chance. Say: In both is great sin, and (some) utility for men; but the sin of them is greater than their usefulness. And they ask thee what they ought to spend. Say: that which is superfluous. Thus Allah maketh plain to you (His) revelations, that haply ye may reflect.

(2) Allah chargeth you concerning (the provision for) your children: to the male the equivalent of the portion of two females, and if there be women more than two, then theirs is two-thirds of the inheritance, and if there be one (only) then the half. And to each of his parents a sixth of the inheritance, if he have a son; and if he have no son and his parents are his heirs, then to his mother appertaineth the third; and if he have brethren, then to his mother appertaineth the sixth, after any legacy he may have bequeathed, or debt (hath been paid). Your parents and your children: Ye know not which of them is nearer unto you in usefulness. It is an injunction from Allah. Lo! Allah is Knower, Wise.

(3) And he of Egypt who purchased him said unto his wife: Receive him honourably. Perchance he may prove useful to us or we may adopt him as a son. Thus we established Joseph in the land that We might teach him the interpretation of events. And Allah was predominant in His career, but most of mankind know not.