Let's break down the problem step by step:
Original cost breakdown:
Labor : Materials : Consultancy = 5 : 12 : 3
This means the original cost can be divided into 20 equal parts (5 + 12 + 3 = 20 parts).
Original cost of labor = (5/20) * 120,000 = GHe 30,000
Original cost of materials = (12/20) * 120,000 = GHe 72,000
Original cost of consultancy = (3/20) * 120,000 = GHe 18,000
Now, let's calculate the increases:
Labor cost increased by 21%:
New cost of labor = Original cost of labor + 21% of Original cost of labor
New cost of labor = 30,000 + 0.21 * 30,000 = GHe 36,300
Materials cost increased by 2.5%:
New cost of materials = Original cost of materials + 2.5% of Original cost of materials
New cost of materials = 72,000 + 0.025 * 72,000 = GHe 73,800
Consultancy fee remains unchanged, so it's still GHe 18,000.
Now, we're given that the new cost of labor is two-fifths (2/5) of the new cost of materials, so:
New cost of labor = (2/5) * New cost of materials
36,300 = (2/5) * New cost of materials
Now, let's solve for the new cost of materials:
New cost of materials = 36,300 / (2/5) = 36,300 * (5/2) = GHe 91,125
Now, we can find the new total cost of building the house by adding the new costs of labor, materials, and unchanged consultancy fee:
New total cost = New cost of labor + New cost of materials + Consultancy fee
New total cost = 36,300 + 91,125 + 18,000 = GHe 145,425
So, the new cost of building the house is GHe 145,425.
(a) The value of y was not defined in the original problem, so I can't provide an answer for that part without more information.
sorry if this is wrong, im learning and trying :)