Answer:
(d) 60 ≤ 1.36x + 34 ≤ 85; To stay within the range, the usage should be between 19.1 and 37.5 HCF
Explanation:
You want an inequality and its solution for the recommended range of water consumption, given water is billed at $34 plus $1.36 per hundred cubic feet (HCF), and the recommended bill is between $60 and $85.
Bill amount
For x hundred cubic feet of consumption, the charge will be 1.36x. When that is added to the $34 monthly fee, the monthly bill is 1.36x +34.
Since it is recommended this amount be between $60 and $85, we can write the inequality as ...
60 ≤ 1.36x +34 ≤ 85
Consumption
Solving this inequality for x, we have ...
26 ≤ 1.36x ≤ 51 . . . . . . . subtract 34
19.1 ≤ x ≤ 37.5 . . . . . . . divide by 1.36, round to 1 dp
To stay within the recommended range of water consumption, the usage should be between 19.1 and 37.5 HCF.
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