Time Speed and Distance Time, speed and distance are related to each other by the formulae Distance = Speed X Time Speed = Distance ÷ Time Time = Distance ÷ Speed

To remember them use the triangle shown. Fill in the letters alphabetically starting at the top Distance = Speed X Time Speed = Distance ÷ Time Time = Distance ÷ Speed D ST

Distance = Speed X Time Speed = Distance ÷ Time Time = Distance ÷ Speed D ST 1.A car travels at 30 mph for 2 hours. How far has it travelled? ie Find D D = S x T  D = 30 x 2  D = 60 miles

Distance = Speed X Time Speed = Distance ÷ Time Time = Distance ÷ Speed D ST A cyclist travels 45 miles in 3 hours. What is the cyclist’s speed? i.e find S S = D ÷ T  S = 45 ÷ 3  S = 15 mph

Distance = Speed X Time Speed = Distance ÷ Time Time = Distance ÷ Speed D ST A plane covers a distance of 1200 miles at a speed of 300 mph. How long will it take to complete this journey? Find T T = D ÷ S  T = 1200 ÷ 300  T = 4 hours

If the time is in hours and minutes, change it to hours and decimal parts of a hour like this: 2 hours 24 minutes = 24 ÷ 60 = hours

Distance = Speed X Time Speed = Distance ÷ Time Time = Distance ÷ Speed D ST A car travels 105 miles in 2 hours 18 minutes. What is the cyclist’s speed? i.e find S Convert 18 minutes into hours 2 hours 18 minutes = 2.3 hours 18 ÷ 60 = 0.3

Distance = Speed X Time Speed = Distance ÷ Time Time = Distance ÷ Speed D ST A car travels 105 miles in 2 hours 18 minutes. What is the cyclist’s speed? i.e find S S = D ÷ T  S = 105 ÷ 2.3  S = mph

Intermediate Maths Ex 11.1 pg 115 No.s 1, 3, 5, 7, 8, 13 to 25

Distance time graphs Scale: Time 6 squares = 24 mins 1 square = 4mins Distance5 squares = 5km 1 square = 1km

Distance time graphs The graph shows the distance steadily increasing for 20 mins No increase in distance for 16 mins i.e waiting for 2 nd bus Steadily increasing distance for another 16 mins

Distance time graphs a)Distance to Grans = 12km b)Waiting time = 16 mins

Distance time graphs c)Speed 1 st bus = distance ÷ time Distance = 7km Time = 20 mins = 20 ÷ 60 hours = hours Speed = distance ÷ time = 7÷ = 21km/hr

Distance time graphs c)Speed 2nd bus = distance ÷ time Distance = 5km Time = 16 mins = 16 ÷ 60 hours = hours Speed = distance ÷ time = 5 ÷ = 18.75km/hr

Scale: Time 10 squares = 1 hour 1 square = 6mins Distance10 squares = 50km 1 square = 5km

a) B arrives 2 hrs 6 mins A arrive at 2 hrs 12 mins : B arrives first 1 square = 6mins

b) A stays for 7 x 6 mins = 42 mins 1 square = 6mins

c) Together for 5 x 6 mins = 30 mins 1 square = 6mins

d) Speed A = distance ÷ traveling time Distance = 130km Traveling Time = 16 x 6 = 96mins = 96 ÷ 60 hours = 1.6hours Speed = distance ÷ time = 130 ÷ 1.6 = 81.25km/hr 1 square = 6mins

d) Speed B = distance ÷ traveling time Distance = 120km Traveling Time = 21 x 6 = 126mins = 126 ÷ 60 hours = 2.1hours Speed = distance ÷ time = 126 ÷ 2.1 = 60km/hr 1 square = 6mins