In the Holy Quran Allaah says,( interpretation of the meaning ) ” Allaah will not punish you for what is unintentional in your oaths, but He will punish you for your deliberate oaths, for its expiation ( a deliberate oath ) feed ten poor persons on a scale of the average of that with which you feed your own families, or clothe them, or manumit a slave. But whosoever cannot afford ( that ), then he should fast for three days “.( Al-Ma’idah 5 : 89 ). 

From the above meaning I have some doubt on the following, so please clear me. 

1. Feed ten persons means by giving food to each person equal to what I feed my whole family depend on me or equal to what I feed only one member of my family at one time or one day. 

2. Is it permissible to give the cost of food by cash or not.

Praise be to Allaah. 

What
is meant by feeding (a poor person) is half a saa’ of the staple
food of the country, such as dates, wheat, etc. This is equivalent to approximately
one and a half kilograms of rice. See
Question # 9985.

 With
regard to giving the price of the food instead of the food itself, the correct
view is that giving the price does not fulfil the conditions of the kafaarah
(expiation). This is the view of the majority of scholars. Ibn Qudaamah said
in al-Mughni: “The kafaarah is not achieved by paying the
price of the food or clothing, because Allaah mentioned giving food, so the
kafaarah is not achieved by anything else. Allaah gives us the choice
of three things’ if it were permissible to give the price, the choice
would not have been limited to these three…” (al-Mughni by
Ibn Qudaamah, 11/256) 

See
Fataawa Islamiyyah, 3/464; Kitaab al-Aymaan wa’l-Nudhoor,
Muhammad ‘Abd al-Qaadir, 87. 

And
Allaah knows best.