(1) The Principal Act is amended -

(a) in section 47 -

(i) in subsection (4) (a) by substituting "twenty-fourth" for "twenty-second",

(ii) in subsection (5) (b) by substituting "22" for "18", and

(iii) in subsection (5) (c) (ii) -

(I) by substituting "twentieth" for "sixteenth" in each place where it occurs, and

(II) by substituting "thirty-second" for "twenty-fourth" in each place where it occurs,

and

(b) in section 49(1) (a) by substituting "80 per cent" for "75 per cent".

(2) The Principal Act is further amended in section 47(4) (a) (as amended by subsection (1) (a) (i) of this section) by substituting "thirty-second" for "twenty-fourth".

(3)