To solve this problem,you need to use the formula d = rd (distance = rates x time)She runs at a speed of 7 mph and walks at a speed of 3 mph. Her distance running is d = 7trwhere tr is the time she spends running Her distance walking isd = 3twwhere tw is the time she spends walking The distances are the same so7tr = 3tw We also know that the total time is 4 hourstr + tw = 4tr = 4-tw Substitute this value of tr in the first equation7tr = 3tw7(4-tw) = 3tw28-7tw = 3tw28 = 10tw2.8 = tw Denise will spend 2.8 hours (2 hours, 48 minutes) walking back and 1.2 hours (1 hour, 12 minutes running.
Hope I helped :)
Implicit expression refers to equation that are not strictly expressed in terms of y and x separately. In this case, the derivative of expression
<span>sqrt(xy)=x^2y+1 is
sqrt x * 0.5 y ^-0.5 dy + </span>sqrt y<span> * 0.5 x ^-0.5 dx= x^2 dy + 2xy dx
dy (x^2 - 0.5 (</span>x/y) ^0.5) = dx (2xy - 0.5 (y<span>/x)^0.5)
dy/dx = </span>(2xy - 0.5 (y/x)^0.5) / (x^2 - 0.5 (<span>x/y) ^0.5)</span>
x = total amount of students in 8th Grade.
we know only one-thrid of the class went, so (1/3)x or x/3 went.
we also know 5 coaches went too, and that the total amount of that is 41.
now, to verify, well, what do you get for (108/3) + 5?
