Hey, I have the following dataset:

ID OfferBy Amount offered (€)
1 Samsung 100
1 Apple 125
1 Nokia 250
1 Blackberry 300
2 Apple 150
2 Nokia 220
2 Blackberry 240
3 Nokia 300
3 Apple 150
3 Blackberry 100
3 Samsung 50
I would love to get the ratio (division) of: Those offers which are both offered by Samsung and Apple to the same id
and this would be divided by the sum of all offers.



For example, because ID 1 has both offers from Samsung and Apple, it meets my condition and the sum of offers from Samsung and Apple (100 + 125) would be added to the numerator. ID2 wouldn't be taken into account because only Apple has made an offer but Samsung hasn't. ID 3 would be added to the numerator because it has offers from both Samsung and Apple (150 + 50).

This would be divided by the sum of all offers.

Any help would be appreciated