not sure if this can help but if you say for each friend, of course its 5 but if you see it as the total of the candles he will give his all his friends, find the nearest multiple of five and we can say that it is 45 and that he'd give them to 9 of his friends.
1. two multiplied by a
3. x added by 3
4. y decreased by 4
5. 5 is added to the product of 2 times f