The answer is AA
good luck
Answer:
£110
Step-by-step explanation:
We know how much time it takes for a boiler and a radiator, and we need to know how much it will cost for 1 boiler and 4 radiators. We have an initial cost of £30, and since hes doing a boiler - which we know takes an hour - we can already add £20 for a start of £50.
Now, there are 4 radiators, that take 45 minutes each. We need to use this equation:

We divide by 60 because there are 60 minutes in an hour, and he charges by hour. So:

Now, to find out how much to charge, we need to figure out how much to add to the £50. Since it's £20 an hour, and it takes 3 hours to do the 4 radiators, we need to multiply:

Now we add our totals for a grand total of...

D they all have the same slope.
Remark
Whatever the original price, he gets 70% in the first instance.
He gets 80% in the second instance.
He gets 90% in the third instance
His total income is 240 dollars.
Let the original price be x
Equation
70%x + 80%x +90%x = 240
70% = 0.7 ; 80% = 0.8 ;90% = 0.9
Solution
0.7x + 0.8x + 0.9x = 240 Take out x as a common factor and add the decimals.
x (0.7 + 0.8 + 0.9) = 240
2.4x = 240 Divide both sides by 2.4
x = 240/2.4
x = 100
So the watches should have brought in 3*100 = 300 dollars.
He only brought in 240 dollars.
He lost 300 - 240 = 60 dollars.
The answer is B.