Making Maths Count
Maths Week Scotland 2019 – The Extension
Problem 4: The Extension
A contractor was planning a small extension to a house and subcontracting the work to six tradespeople. For some peculiar reason, she worked out what she would have to pay in total to certain pairs of them, as follows:
a) £18000 to the builder and the joiner
b) £9000 to the joiner and the roofer
c) £3800 to the roofer and the plasterer
d) £1500 to the plasterer and the electrician
e) £1200 to the electrician and the plumber
f) £6500 to the plumber and the joiner.
How much did she pay to each tradesperson individually and what was her total outlay?
Solutions to Problem 4:
From b) and c), the joiner gets £5200 more than the plasterer.
From d) and e), the plasterer gets £300 more than the plumber.
So the joiner gets £5500 more than the plumber.
But from f), the joiner and the plumber get £6500 between them.
So the joiner gets £6000 and the plumber gets £500.
From e), the electrician gets £700.
From d), the plasterer gets £800.
From c), the roofer gets £3000.
From a), the builder gets £12000.
The total outlay is the sum of the payments to the six, i.e. £23000.