There were 3 containers, A, B and C of sand. Container A contained twice as much sand as Container B. After 15% of the sand in Container A and 20% of the sand in Container B were transferred to Container C, the amount of sand in Container C increased by 20%. In the end, Container C contained 2.47 kg more sand than Container A. How much more sand did Container C have than Container B? 12% ​