Advanced MathEasyWhere a thrown stone lands
Advanced Math practice question
A stone thrown across a river is at a height of 100 − x² metres when it is x metres horizontally from the thrower. How many metres from the thrower, horizontally, does the stone land in the river?
Answer: 10
100 − x² = 0 gives x² = 100, so x = 10.
Common wrong answers
- If you answered 5
- 5 halves 10.
- If you answered 50
- 50 halves 100.
- If you answered 100
- 100 is x², not x.
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