In the market fruit stand, they have the following offers:

1kg of apples + 1kg of oranges cost € 4.30

1 kg of bananas + 1 kg of oranges cost € 3.70

1kg of apples + 1kg of bananas cost € 3.60

**How much does a kilo of bananas cost?**

#### Solution

If we define the following variables:

M = 1 Kg of Apples

P = 1 Kg of Bananas

N = 1 Kg of Oranges

We can rewrite the statement as follows:

M + N = 4.30

P + N = 3.70

M + P = 3.60

And clearing we get that

M = 4.30 - N

N = 3.70 - P

P = 3.60 - M

Where can we deduce

M = 4.30 - (3.70 - P) = 4.30 - (3.70 - (3.60 - M))

M = 4.30 - 3.70 + 3.60 - M

2M = 4.30 - 3.70 + 3.60 = 4.20

M = 2.10

Substituting in the third equation we obtain that

P = 3.60 - 2.10 = 1.50

And finally

N = 3.70 - 1.50 = 2.20.

M = 2.10

N = 2.20

P = 1.50

Thus **the kilo of bananas costs € 1.50**