Hey there!
=> [tex]550 \times \frac{22}{100} [/tex]
=> [tex] \frac{550}{1} \times \frac{22}{100} [/tex]
cancel the zeros of 100 and 550
=> [tex] \frac{55}{1} \times \frac{22}{10} [/tex]
=> [tex] \frac{1,210}{10} [/tex]
=> 121 ( Substract 121 from 550)
=> 429
Therefore, Selling price is 429