Convert from bag [portland cement] to arroba [Spain]

Unit Definition (bag [portland cement])
The bag [portland cement] is a unit of weight for cement. Traditionally a bag of portland cement weighs 94 pounds (42.6 kilograms) in the US. and 87.5 pounds (39.7 kilograms) in Canada. However, cement is now being sold also in metric-sized bags of 50 kilograms (110.2 pounds) by many suppliers.

Unit Definition (arroba [Spain])
The arroba [Spain] is a traditional unit of weight in Spain and Portugal, equal to 1/4 quintal. However, the Spanish and Portuguese quintals are of different sizes. In Spain, the arroba equals 25.36 pounds (11.50 kilograms); arrobas of very similar sizes were established in the Spanish speaking countries of Latin America. The arroba has also been used as a metric unit equal to exactly 15 kilograms. The name of the unit comes from ar rub', Arabic for "the quarter."