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Math Challenge I-C Handout 4

 
 
ZhouWanyang的头像
Math Challenge I-C Handout 4
ZhouWanyang - 2017年10月6日 Friday 11:16
 

I don't understand 4.30. Can anyone help me?

Question 4.30:

Dylan dives from a platform that is 4040 feet high. Dylans mom wants to take a picture right when Dylan is at the same heigh as her. Dylan's height above the water after tt seconds is h(t)=16t2+8t+40h(t)=−16t2+8t+40. If Dylan's mom is sitting 1010feet above the water, how much time will pass before his mom takes the picture?


 
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Re: Math Challenge I-C Handout 4
ZhouWanyang - 2017年10月6日 Friday 14:00
 

Can anyone at least give me a hint?

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Re: Math Challenge I-C Handout 4
ProfessorAreteem - 2017年10月6日 Friday 15:05
 

The problem gives us an equation for Dylan's height at time $t$:  $h(t)=−16t^2+8t+40$ (measured in feet). We know that Dylan's mom wants to take a picture when his height is $10$ feet (because that is the height she is sitting). Therefore we should be able to use the equation to determine when Dylan is at $10$ feet.

Hope this helps!

ZhouWanyang的头像
Re: Math Challenge I-C Handout 4
ZhouWanyang - 2017年10月6日 Friday 19:50
 

Thank you  :)