The first one shown, 400/2, is showing the point on the graph where she walks 400 ft in 2 minutes. In order to find the next proportion, you just have to look two minutes over which in this case is 800 ft for 4 minutes... written 800 over 4.
1/1.5 * 10^-6 = 2500/x
x = 1.5 * 10^-6 * 2500
x = 0.00375 or 3.75 * 10^-3 second.
<span><span>∑<span>i=2</span><span>i=10</span></span>(4+2n)=</span><span>
You can do it by hand, w/o much work .
plug in n=2 into (4+2n)
then plug in n=3 into (4+2n)
then plug in n=4 into (4+2n)
etc until you get to n=10. Add them all up.
</span><span>add 8 + 10 + 12 + 14 + 16 + 18 + 20 + 22 + 24
</span><span>144 jumps!</span>
