a)
[tex] \bf{rate = \frac{1}{4} } \\ \bf \: gaini = \frac{4}{4} - \frac{1}{4} = \frac{3}{4} [/tex]
b) [tex] \bf \: \frac{1}{4} < \frac{3}{4} ✓[/tex]
[tex] \bf \: rate = 8 \times \frac{1}{4} = \frac{8}{4} = \boxed2✓[/tex]
[tex] \bf \: gaini = 8 - 2 = \boxed6✓[/tex]