Let the first basket be called A, the second basket be called B, and the eggs be called E.
63E + A = 1008
54E + B = 891
as the baskets weigh the same, A=B
63E + B = 1008
54E + B = 891
Rearranging for B gives
B =1008 - 63E
B= 891 - 54E
as B=B, these two are equal
1008 -63E = 891 - 54E
subtracting 891 from both sides,
117 - 63E = -54 E
adding 63E to both sides gives
117 = 9E
dividing both sides by 9
13 = E
therefore each egg weighs 13gms.
putting this answer back into the equation
B=891-54E
gives B=891-(54*9)
B= 891 - 486
B = 405 gms