1.
Solution here,
let the both planes covers same distance x while over taking.
For the small plane, let time be t.
speed= 240 mph
now,
distance covered by it,
x=240t--------(1)
For jet plane,let the time be t'.
speed=36mph
since it is flewed after 30 mins, it can be written as,
t'=t-30 min=t-0.5 hr
now distance covered by it,
c=360t'=360(t-0.5)=360t-180----------(2)
equating (1) and (2)
240t=360t-180
or, -120t=-180
or, t=1.5 hr
therefore two planes wiil meet after 1.5 hrs.
putting the value of t in (1)
x=240×1.5=360 m
therefore they travel through 360 m from the airport whlie over taking.
2.
For the first car,
speed=50 Kmph
let it covers x distance at time t
so,diatance x=50t--------(1)
For the second car,
speed=45 Kmph
according to the question, in time t, it will covers the distance (x-20)Km
so, distance(x-20)=45t
or, x=45t+20---------(2)
equating (1) and (2),
50t=45t+20
or, 5t=20
or, t=4 hrs.
therefore cars will be apart of 20 km after 4 hrs.
