54 ..........150%
x .............100%
x =100*54/150 = 36
Everything is false besides 2
THe amplitude is half of the distance from the highest and lowest phase of the wave..
4-(-1)=5
0.5*5=2.5
amp=2.5 units
15$ I believe, as we can disregard the two original books (they have been payed for) leaving her to buy 1 book and having seven dollars, however if she needs $8 more you simply need to add 8+7.
