Please help with my daughters homework

Question

vshiroky · Answer

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danjs · Answer

Number 12 , you multiplied by the wrong fraction. The way it is set up, you see the units multiply out to.. ( k * k)/(hr * mi)  ,  not mi/hr

vshiroky · Answer

Oh I fixed that one to flip flop... I noticed it was incorrect so that one was fixed

vshiroky · Answer

The one I need help on for her is number 14

danjs · Answer

$$\frac{ 85~k }{ 1~hr }*\frac{ 0.6214~mi }{ 1~k } = \frac{ 85*0.6214~~mi }{ 1~~hr }$$

vshiroky · Answer

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danjs · Answer

oh ok.. 
45 mi/hr  for  45 min.  You need to change one of them so the time unit is the same

vshiroky · Answer

would that be the correct way to set it up? thats over 1 hour not i hour

danjs · Answer

Not exactly...

The distance traveled equals the speed times the time traveling.. 
Distance = speed * time

vshiroky · Answer

oh?

danjs · Answer

You can change the 45 min to hours first to match units.. notice how minutes cancels on top and bottom
$$\frac{ 45~~\min }{ 1 }*\frac{ 1~~hr }{ 60~~\min }=\frac{ 3 }{ 4 }~~hr$$

mathmale · Answer

Is there any way in which you could involve your daughter in this conversation?  Can you discern, by talking with her, what she understands and what she does not?

danjs · Answer

So 45 mi/h for 3/4 of an hour is

$$Distance =\frac{ 45~~mi }{ 1~~hr }*\frac{ 3/4~~hr }{ 1 }=33.75~~mi$$