想問呢句英文係咩意思[Maths]

At noon, two ships A and B departed from a point O and sailed along different courses at constant speed . The angle between the two
courses at was 60°

a)At 3 p.m. the same day, the line joining the positions of the ships
was perpendicular to the course of ship B. If the speed of ship A was
30 km/h, find the speed of ship B .

b)At 3 p.m. the same day, both ships kept their previous speeds and
silled towards each other untill they met at point P . Find the size of
the angle between OP and the original course of ship A.

只需要知道 b) 個句.......

唔該 .........................