Answer:
<4= 164
Step-by-step explanation:
the sum of any 2 angles of a triangle is equal to the exterior linear angle of the triangle
<1+<2=<4
8x+9+5x+12=14x+10
13x+21=14x+10
21=x+10
11=x
<4=14x+10
<4=14(11)+10
<4=154+10
<4= 164
Answer: 
Step-by-step explanation:
Given
River is flowing from south to North with a velocity of 
Motor boat traverses the river from east to west at a speed of 
South component of boat velocity must compensate the river velocity in order to travel in west direction.

You have to know how long it takes them both to solve the puzzles. ;)