Is it permissible for a girl whose family relies for their livelihood on interest from usurious banks to work in order to provide halal money to help a committed and poor young man get married, and is this work considered a necessity? And is it permissible for her to buy clothes, jewelry, sweets, and food luxuries from the mixed money her father gives her from bank interest?

It is not permissible for a woman to work as a teacher in a mixed school for boys and girls at the secondary level, due to the temptation (fitna) it entails, the forbidden mixing, and the endorsement of evil. Her desire to help a young man get married is not considered a necessity that would permit this work.

If all of the father's money comes from usurious interest, then it is not permissible to benefit from it except in cases of extreme necessity, such as having no other source of income, and only to the extent of the need. The father must be advised to abandon dealing with usury.