(i) If the speed of an aeroplane is decreased by 120 km/h, it takes 18 minutes more
to travel some distance. If the speed is increased by 180 km/h, it takes 18 minutes
less to travel the same distance. Find the average speed of the aeroplane and the
distance.
Answers
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1
Answer:
Step-by-step explanation:
LET THE DISTANCE BE X
TIME BE T
SPEED=DISTANCE /TIME
CASE 1:
120=X/(T+(18/60))
120=X/(T+0.3)
X= 120T +36 (1ST EQUATION)
CASE 2:
180=X/(T-(18/60))
180(T-0.3)=X (2ND EQUATION)
FROM 1 AND 2
120T+36=180T-54
60T=90
T=1.5 HRS
X=12*18
=216 KM
AVERAGE SPEED =216/1.5
=144 KM/HR
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