Question

Need help with question 13B i can not figure it out please help.

Answer 1

Short Answer 10
The tough part is the number of drinks.
Let the number of them be x
4.5 x + 3 + (10/100) * (4.5x + 3) + (7/100) * (4.5 x + 3) ≤  60

The tip is not included in the tax, and the tax does not include the tip. You can shorten this up quite a bit.
4.5 x + 3 + (10/100) * (4.5x + 3) + (7/100) * (4.5 x + 3) ≤  60
(1 + 10/100 + 7 /100) (4.5x + 3) ≤  60     Combine the tax, tip, scone and Lattes 

(1.17) * (4.5x + 3) ≤ 60                            Divide by 1.17
4.5x + 3 ≤ 60 / 1.17 
4.5x + 3 ≤ 51.28                                      Subtract 3
4.5x ≤ 48.28                                            Divide by 4.5
x ≤ 48.28 / 4.5
x ≤ 10.72 

Discussion.
There's a problem. He can't buy 0.72 of a Latte. He can only buy 10 of them. In this case we must round down so what happens if he buys 10 lattes? Does the price the taxes and the tip allow him to get another Latte? The answer should be no because then you would be 11 lattes and the tip and taxes would push you over 60 dollars. But be careful, sometimes things like this can alter you answer.. 

Answer: 10 <<<<