The best thing to do here is to divide $4.85 by 10, and then multiply it by 2.5. $4.85/10= $0.48. $0.48x2.5= $1.20
Therefore,the discount is $1.20, you've then got to subtract this from $4.85. $4.85-$1.20= $3.65
$3.65 is the sale price of the pizza.
Hope this helps :)