Answer: 52.94
Step-by-step explanation:
Length of train A = 480m
Tunnel length = 1320m
Time taken to cross tunnel = 2 mins = 120sec
Length of train B = 420m
Train B is slower than train A
Difference between their speed = 18km/hr
18km/hr = (18×1000)/3600 = 5m/s
Speed of train A :
Speed = distance / time
Speed = 1320 / 120 = 11m/s
Therefore, speed of train B :
(11 - 5)m/s = 6m/s
Relative speed of the two trains is therefore;
(Speed of A + speed of B)
Note : they are moving in opposite direction
( 11 + 6)m/s = 17m/s
Therefore time taken to cross each other :
(Sum of the length of both trains / relative speed of the trains)
Time taken = (480m + 420m) / (17m/s)
Time taken = 900m / 17m/s
Time taken = 52.94s
This is a right triangle. To find the length of the hypotenuse a^2 + b^2 = c^2.
21^2 + 18^2 = c^2
441 + 324 = c^2
765 = c^2
27.66 km
Step-by-step explanation:
In parallelogram Both pairs of opposite sides are parallel
a = 30
a = 16
-a² + 46a -480 = 0
(-a + 30) (a -16) = 0
(-a)(a) + (-a)(-16) + 30(a) + 30(-16) = 0
-a² + 16a + 30a -480 = 0
-a² + 46a - 480 = 0
(-a + 30) = 0 ; (a - 16) = 0
-a = -30 ; a = 16
a = 30
To check:
a = 30
-(30)² + 46(30) - 480 = 0
-900 + 1380 - 480 = 0
480 - 480 = 0
0 = 0
a = 16
-(16)² + 46(16) - 480 = 0
-256 + 736 - 480 = 0
480 - 480 = 0
0 = 0
