D = 545.79
r = 48.3
Plug in numbers to corresponding variables
545.79 = t(48.3)
Isolate the t, divide 48.3 from both sides
(545.79)/48.3 = 48.3t/48.3
t = 545.79/48.3
t = 11.3
t = A) 11.3 h
hope this helps

Since all the variables cancel out and the coefficient equal to eachother, this system of equation has
<u>infinitely many solutions!</u>
90+55+75+60+80+90=450
450/6=75