Question

The local time at the longitude 15degree east of the prime meridian is _______ *

a) behind the GMT by 1 hours
b)behind the GMT by 2 hours
c)ahead the GMT by 1 hour
d)ahead the GMT by 2 hour
what is the answer

Answer 1

Explanation:

Let BC be the width of river. And ∡ of depression on either side of the river are 30

0

and 60

0

.

It is given that

AC=20 m

Let BC=x ,CD=y, ∠ABC=30

0

, ∠ADC=60

0

In △ABC,

tanB=

BC

AC

=

x

20

=

3

1

⇒x=20

3

In △ADC,tan60

0

=

y

20

y=

3

20

3

x+y=

3

80

m= width of river