Can somebody me solve
"andy buys a top hat that has been reduced in a sale by 35%. if the sale price is £13, what was its original price? "

35% of the original price was slashed off of it.
So 65% of it remained.
That's the  £13 . . . 65% of the original price.

65% means 0.65.

                                   0.65 x (original price) =  £13 .

Divide each side by 0.65:      Original price = £13/0.65

                                                                        = £20 .