Question 275675
r*t=d
(b+5)*t=220
(b-5)*t=180
t=220/(b+5)
t=180/(b-5)

220/(b+5)=180/(b-5)
220(b-5)=180(b+5)
220b-220*5=180b+180*5
40b=400*5=50*40
b=50