In case of slotted aloha, Efficiency = G*e^(-1*G). Where G stands for 'number of stations wanting to transmit'. In case of slotted Aloha G=1.
So, Throughput= Efficiency * (Bandwidth given).
In slotted aloha for maximum efficiency value will be 36.8%.
So, in case of max efficiency Throughput = (36.8%) * Bandwidth given.
( If I am wrong then I am open to understand more always.)