Answer:
Total number of sweets in the bag is 28
Step-by-step explanation:
let the total number of sweets in the bag be x :
[tex]{ \tt{for \: toffees : }} \\ \frac{1}{4} \: of \: x[/tex]
therefore fraction of mints = 1 - fraction of toffees :
[tex] = \frac{4}{4} - \frac{1}{4} \\ \\ = \frac{3}{4} [/tex]
therefore:
[tex] = > \frac{3}{4} \: of \: x = 21 \: mints \\ \\ \frac{3}{4} \times x = 21 \\ 3x = 21 \times 4 \\ x = \frac{21 \times 4}{3} \\ x = 28[/tex]
total sweets number is 28