Answer:
she spend $600 more on phone than on bag.
part A:
let the money she have be m,
she spent on mobile phone: [tex]\sf m * \frac{4}{5}[/tex] → [tex]\sf \frac{4}{5}m[/tex]
remaining: [tex]\sf m-\frac{4}{5}m[/tex] → [tex]\sf \frac{1}{5}m[/tex]
she spent on bag: [tex]\sf \frac{1}{5}m * \frac{2}{3}[/tex] → [tex]\sf \frac{2m}{15}[/tex]
remaining: [tex]\sf \sf \frac{1}{5}m - \sf \frac{2m}{15}[/tex] → [tex]\sf \frac{1}{15}m[/tex]
so,
[tex]\sf \frac{1}{15}m[/tex] = 60
m = $900
part B:
money she spent on mobile phone: [tex]\sf \frac{4}{5}m[/tex] → [tex]\sf \frac{4}{5}(900)[/tex] → $720
money she spent on bag: [tex]\sf \frac{2m}{15}[/tex] → [tex]\sf \frac{2}{15} * 900[/tex] → $120
more money she spent on mobile phone than on bag:
mobile phone cost - bag cost
720 - 120
$600
