Question

A car is being driven, in a straight line and at a uniform speed, towards the base of a vertical tower. The

top of the tower is observed from the car and, in the process, it takes 10 minutes for the angle of elevation

to change from 45° to 60°. After how much more time will this car reach the base of the tower?​

Answer 1

Answer:

I hope it is helpful

Step-by-step explanation:

Let speed of can be vm/min

⇒BC=v×12

In ΔAOC,tan30=

OC

AO

⇒

3

1

=

OC

AO

In ΔAOB,tan45=

OB

AO

⇒1=

OB

AO

⇒OC=

3

AO=

3

OB

⇒OB+BC=

3

OB

⇒OB(

3

−1)⇒BC⇒

BC

OB

=

3

−1

1

Now, t=

v

OB

=

v(

3

−1)

BC

=

3

−1

12

×

3

+1

3

+1

t=6(

3

+1)min