Question

a streamer goes downstream and covers the distance between two parts in 5hrs while it covers the same distance upstream in 6hrs. if the speed of the stream is 1km/hr find the speed of the steamer in still water​

Answer 1

In ||gm ABCD,

∠A + ∠B = 180°

(Sum of consecutive angles) But, ∠A = 75°

∴ ∠B = 180° – ∠A = 180° – 75° = 105°

∴ DBA = 105° -60° = 45°

But ∠CDB = ∠DBA (alternate angles)

= 45°

and ∠ADB = ∠DBC = 60°