Substitution on the farm.
Mr Johnson
Farm song
http://www.youtube.com/watch?v=fJyfh-9b8ZA
http://www.youtube.com/watch?v=w6ySjiDl6-4
CODEWORDS.
If this is the code…
A=1, B=2, C=3, etc.
What does this say? 9 12,15,22,5 8,1,19,8,18
Can you make up your own code and write
a sentence for person next to you to solve?
Ploughing and Sowing.
Farmer Fred wants to plough and sow
his field?
So what information
do we need?
So we need to know…
• The size of the field.
• The size of the plough.
• The size of the seed drill.
• The cost of the seed.
• The speed of the tractor with
the plough and seed drill..
• Labour cost.
• Fuel cost.
2
4
3
1
2
4
1
3
Tractor
1
2
3
4
Price (a) Age (b)
£12,000 15 years
£25,000 12 years
£100,000 0 years
£1,500 19 years
kpl (c )
12
9
15
8
Plough
1
2
3
4
Price (f)
£15,000
£3,000
£2,500
£8,000
Age (g)
0 years
8 years
10 years
5 years
Width (h)
10m
5m
3m
6m
Seed drill
Price
1
£1,200
2
£1,750
3
£20,000
4
£13,000
Age (k)
5 years
3 years
0 years
2 years
Width (l)
6m
2m
5m
4m
kph with plough (d)
8
5
11
8
kph with seed drill (e)
6
5
5
5
Labour cost (i) = £15 per hour
Size of field ( x by y) = 150m by 300m
Red diesel per litre (j) = £0.85
Maintenance cost of farm plant = £500 per year.
1 acre = 4004 square metres.
Tractor turning circle (n) = 10.5m
Seed type
£ per kg (p)
kg needed per acre (q)
1
2
3
4
£12
£24
£23
£13
3
4
2
5
1 gallon = 4.4 litres
What now?
• Choose a tractor and plough.
• Calculate the cost of ploughing the field using your chosen
tractor.
• Devise your own formulas for calculating the seed costs.
• Present your findings clearly of the A3 sheet.
• Prepare a presentation so that you can share you results
with the class.
Extension.
Can you find the best combination
of tractor and plough?
So what have we learnt?
Letters can be used to
represent variables.
On your Mini Whiteboards…
1.If x = 2 what is x + 2?
2.If y = 3 what is y – 2?
3.If p = 38 and q = 17 what is p + q?
4.If r = 12 and z = 27 what is r – z?
5.If s = 15, t = 2 and x = 5 what is s + t – x ?
NC level 5A
On you Mini Whiteboards…
IF X=1, Y=2, Z=7, R=12, S=25
1. 2X =
2. 3R =
3. 2R + 5Z =
4. 3Z + 2Y – 2X =
On your Mini Whiteboards…
If X=3, Y=6, Z=12, R=25, S=5 solve these...
Now try these in your books…