Question

When servicing a heating boiler and radiators, a plumer knows that the time he will take is given by the formula

time = 1 hour + 45 minutes per radiator

he charges his costumer a call-out fee of £30, plus £20 per hour
how much should a costumer be charged for servicing a heating boiler and four radiators

Answer 1

£110

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:

`(45*4)/60`

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

`180/60=3`

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:

`3*20=60`

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

`50+60=110`