Question

A motorbike running 90Km/h is slowed down to 18Km/h 25S calculate acceleration creterdation

Answer 1

initial velocity(u)= 90km/ hr
final velocity( v)= 18 km / hr
time(t)= 25sec
therefore we know,
V= U + AT
= 18-90 = A× 25
= A= 72/25
AND
RETARDATION= -72/25

HOPE U FIND IT HELPFUL

Answer 2

try using v=u+at using which is 
v=final velocity 
u=inital velocit
a=accleration
t=time
take acceleration as x or a 
and then solve is the a math linear equation question.