
Hope you could get an idea from here.
Doubt clarification - use comment section.
.875 seconds
a=360t
b=280t+(280*.25)
360t=280t+(280*.25)
360t=280t+70
80t=70
t=.875
So you are finding M
90+x+15+3x+15=180
4x=60
X = 15
LMN = 15+15
LMN = 30
hopefully this is correct :)
D. (I used 3.14 as pi so my answer was a little off so I just went with the one closest to my answer)