Placing three trees in triangle and placing the fourth tree in center
Answer: 66.67 km approx.
Solution:
Let the first train A move at u km/h.
Let the second train B move at v km/h.
Let the distance between two trains be d km
Let the speed of bee be b km/h
Therefore, the time taken by trains to collide = d/(u+v)
Now putting all the known values into the above equation, we get,
u = 50 km/hr
v = 70 km/hr
d = 100 km
b = 80 km/hr
Therfore, the total distance travelled by bee
= b*d/(u+v)
= 80 * 100/(50+70)
= 66.67 km (approx)
TWICE
Green bricks
In 30 mins- Thief – 20km, Owner – 0km
In 1hr – Thief – 40km, Owner – 25km
In 1.5hrs – Thief – 60km, Owner – 50km
In 2hrs – Thief – 80km, Owner – 75km
In 2.5hrs – Thief – 100km, Owner – 100km
Answer: In 2.5 hours the owner would have overtaken the Theif
B. 32%
speed=mile/hour
.•. time taken to travel M miles is
So, time =distance/speed
=M/m/h
=Mh/m hrs
heat loss from a surface can be reduced by polishing the surface coz polished surface is bad radiator and bad absorber of heat
let x=speed
t=time taken when speed is x so…
xt=4/5x(t+40)
t=160 minutes
2 hr 40 minutes