Question here

give answer in km/h

Here is part of a travel graph of Sian's journey from her house to shops and back Graph is not representing Back journey a) What is the speed of Sian from 30 minutes to 45 minutes? Distance at 30 min = 20 km Distane at 45 min = 20 km Distance from 30 to 45 min = 20 - 20 = 0 km Time = 45 - 30 = 15 min = 1/4 hr Speed = 0/(1/4)  = 0 km/Hr b) What is the distance travelled by Sian in 15 minutes? Let say first 15 min Distance at 0 min = 0 km Distance at 15 min = 10 km Distnace Travelled in 15 min = 10 - 0 = 10 km Time = 15 min = (1/4) hr Speed = (10 - 0)/(1/4)  = 40 km/Hr c) Find out her average speed and express in km/h. Distance Tavelled = 20 km Time = 45 mins = (3/4) hrs Average Speed = 20/(3/4)  = 80/3 Km/HrHOPE IT HELPS (◕‿◕✿)

It says in the questions that it is 6.5?