16Hit1600
AlgebraHardInequality with a bounded quantity

Algebra practice question

A lift can carry at most 630 kilograms. A delivery worker who weighs 80 kilograms rides with boxes of 25 kilograms each. Which inequality gives all possible numbers of boxes b the lift can carry with the worker?

  1. A. 25b + 80 ≤ 630Correct
  2. B. 25b + 80 < 630
  3. C. 25b ≤ 630
  4. D. 80b + 25 ≤ 630

Answer: A. 25b + 80 ≤ 630

Total load = 80 + 25b, which must be at most 630: 25b + 80 ≤ 630 (so b ≤ 22).

Why the other answers are wrong

B. 25b + 80 < 630
'At most' allows equality, so ≤, not <.
C. 25b ≤ 630
Leaves out the worker's weight.
D. 80b + 25 ≤ 630
Swaps the worker's weight and the box weight.

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