Simplify:

21.5 ÷ 5 -1/5 of (20.5 - 5.5)+ 0.5 × 8.5

Using BODMAS rule, we have

21.5 ÷ 5 – of (20.5 – 5.5) + 0.5 × 8.5

= 21.5 ÷ 5 – of 15 + 0.5 × 8.5

= 21.5 × – × 15 + 0.5 × 8.5

= 4.3 – 3 + 4.25

= 4.3 + 4.25 – 3

= 8.55 – 3

= 5.55