AlgebraEasy–MediumTime to reach home from a distance model
Algebra practice question
A cyclist's distance from home, in kilometres, t hours after setting off is given by d(t) = 40 − 15t. After how many hours does the cyclist reach home?
Answer: 8/3 or 2.67
Home is where d = 0: 40 − 15t = 0 → t = 40/15 = 8/3 hours.
Common wrong answers
- If you answered 15
- 15 is the speed.
- If you answered 40
- 40 is the starting distance.
- If you answered 0.375
- 0.375 is 15 ÷ 40, the reciprocal.
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