The slope of the normal to the curve x=at4, y=at5 at t=1 is
−12
−23
15
−45
x=a.t4⇒dxdt=4a.t3
y=a.t5⇒dydt=5a.t4 ⇒dydx=54t
m=(dydx)t=1=54
Slope of normal=−45