Using proportions, the billed amount for the month of June is:
D. $42.50
What is a proportion?
A proportion is a fraction of a total amount, and the measures are related using a rule of three. Due to this, relations between variables, either direct or inverse proportional, can be built to find the desired measures in the problem.
The discount will be applied only for the second half of the month, from June 16 to June 30, hence instead of a discount of 30%, it will count as a discount of 15%, meaning that 85% of the bill will be paid, hence the amount paid will be of:
A = 0.85 x $50 = $42.50.
Hence option D is correct.
More can be learned about proportions at https://brainly.com/question/24372153
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