4 is 20% of 20. Hope this helps!
Let x be marked up price. We have been given that a chemistry set costing $27.50, marked up 32% on cost.



Therefore, mark up price is $8.80.
Since we know that selling price of any item equals the sum of cost and mark-up price of the item.
Let us find selling price of our chemistry set.

Therefore, the selling price of the chemistry set is $ 36.30.
1/2 is written as a decimal as 0.50
A = 80/2 = 40
b = 100/2 = 50
d = 180 - (a+b)
d = 180 - (40+50)
d = 180 - 90
d = 90
figure 1: greater than or equal to -4 because the dot is colored in and its pointing right
figure 2: less than 6 (NOT equal to) because the dot is not colored in and its pointing left
hope this helps :)