If I buy a melon and a coconut, the cost will be £1.19.
If I buy a melon and a pineapple, the cost will be £1.45.
If I buy a coconut and a pineapple, the cost will be £1.40.
What are the individual prices?
Pineapple = 83p, coconut = 57p, melon = 62p.
If we assign the letters P, C and M to the fruits, and work in pence we have:
M + C = 119 (1)
M + P = 145 (2)
C + P = 140 (3)
Using (2) - (1) we have:
P - C = 26 (4)
And (3) + (4) gives:
2P = 166
P = 83
This can then be substituted back into (2) and (3). QED.