Question 1:
Shop A trainers normal price= £85
is off so it becomes

So price becomes:

Shop B trainers normal price= £80
30% is off so it becomes:

So price becomes:

So, Shop B has cheaper trainers.
Question 2:
In a sale all items are reduced by = 30%
On the final day the sale price are reduced by = 20%
On the day before the last day of the sale, the price of the sofa was

As given, on the last day of the sale, the price was again reduced to 80% of the price the day before, so price becomes:
Hence the price was £162.40