a)
Solution,
Given,
Cost for 1 pen = $ 1.50
= 1.50×100 cents
= 150 cents
Cost for 1 ruler = 80 cents
No. of Pens needed to be bought = x
No. of rulers needed to be bought = x+10
Now,
Cost for x pens = x×150 cents
= 150x cents
Cost for (x+10) rulers = (x+10)×80 cents
= 80x cents+800 cents
Then,
Total cost = 150x cents+(80x cents+800 cents)
= 150x cents+80x cents+800 cents
= 230x cents+800 cents
= $(230x ÷ 100)+$(800 ÷ 100)
= $2.3x + $8
Therefore,Louise spent $2.3x and $8 as total amount
b)
Sorry,I dont know inequality