Mrs Tham bought z bottles of oil at $7 each. She gave the cashier $50. [a] Find the change Mrs Tham received in terms of z. (b) If z = 3, how much change did Mrs Tham receive?

a) 50 - 7z

b) $29

Step-by-step explanation:

Please let me know if you want me to add an explanation as to why this is the answer. I can definitely do that, I just wouldn’t want to write it if you don’t want me to :)

(a) 50 - 7z

(b) $29

Step-by-step explanation:

(a) If Mrs. Tham bought z bottles and each bottle costed her $7, the amount she spent is 7z. Since she gave the cashier $50, her change would be 50 minus the amount she spent, which is 7z. So, her change would be 50 - 7z.

(b) If z is 3, then we can plug it into our expression from problem (a):

50 - 7z.

z = 3.

50 - 21 = $29

Please check the answer whether it is correct or not :)