Elliot buy 1 tea and 2 coffees for £3. Elise buy 2 teas and 1 coffee for £2.25.
Work out the cost of one tea and one coffee.
tea: £
O coffee: £

tea: £0.5

              coffee: £1.25

Step-by-step explanation: Let's represent the cost of tea as t and the cost of coffee as c.

Elliot bought two coffees and one tea and paid £3, i.e.,

t + 2c = 3

Elise paid £2.25 for two teas and one coffee, or:

2t + c = 2.25

The system of equations to solve are

t + 2c = 3 (1)

2t + c = 2.25 (2)

One way to solve this system is by substitution:

t = 3 - 2c (3)

Using (3) to substitute in (2):

2(3 - 2c) + c = 2.25

6 - 4c + c = 2.25

- 3c = - 3.75

c = 1.25

Now, to determine t, we can use (1) or (3).

As it is easier, we use (3):

t = 3 - 2(1.25)

t = 0.5

The cost of 1 coffee and 1 tea is £1.25 and £0.5, respectively.

x = -20

Step-by-step explanation:

50 = -2.5x

Divide both sides by -2.5

-20 = x