60% of a number is 90 what is the number?
2 answers:
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Answer:
It will take 5.61 seconds for the coin to reach the stream.
Step-by-step explanation:
The height of the coin, after t seconds, is given by the following equation:
How long will it take the coin to reach the stream?
The stream is the ground level.
So the coin reaches the stream when h(t) = 0.
Multiplying by (-1)
Solving a quadratic equation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots such that
, given by the following formulas:
In this question:
So
Time is a positive measure, so we take the positive value.
It will take 5.61 seconds for the coin to reach the stream.