1.3 Dominic buys a calculator costing £7.50, 3 packets of pens costing £1.80 for each packet and
2 answers:
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Answer:
There are 10 pigs and 30 chickens
Step-by-step explanation:
Let the number of pigs be x
let the number of chickens be y
Then there are 40 heads . So the total number of pigs and chickens is 40
x + y = 40-----------------------(1)
We know that pigs have 4 legs and chickens have 2 legs
4x + 2y = 100----------------------(2)
Solving (1) and (2)
multiply (1) by 2
2x + 2y = 80-------------------------(3)
subtract (3) from (2)
4x + 2y = 100
2x + 2y = 80
----------------------------
2x = 20
----------------------------
x = 10
Now Substituting x in (1), we get
10 + y = 40
y = 40 - 10
y = 30