1800 X {[321 + 218 -(800 - 291)]} :[10000- 5000 - (8 X a + 1342)]} = 5400
1800 X (539 - 509) : [5000 - (8 X a + 1342)] = 5400
1800 x 30 : [( 5000 - (8 x a + 1342)] = 5400
30 : [( 5000- (8 x a + 1342)] = 5400 : 1800
30 : [(5000- (8 x a +1342)] =3
5000 - (8 x a + 1342) = 10
8 x a + 1342 =4990
8 x a = 3648
a = 456.