Simple Maths Question

[hc4361]

I have a total mental block. Please help!

I use 3291 electric units on day rate
1999 units on night rate.

What percentage of my electricity usage is night rate?

Many thanks

[Tilly2]

Roughly 66% or two thirds.

[Baldric]

Off the top of my head, 60.741%

[hc4361]

Thanks both. :)

[sandyRoe]

about 40% ?

[knowabit]

If the amount of units used on night rate are less than the units used on day rate, the percentage would surely be below 50%?

[Tilly2]

Now I have got my calculator handy, it'exactly 60.741%

Baldric, did you do that in your head? I'm very impressed.

[The Builder]

1999 + 3291 = 5290 (total usage)

1999 / 5290 x 100 = 37.78%

[knowabit]

38%, if I have calcualted correctly!

[nescio]

No it isn't.
Sandy is correct.
The percentage usage on night rate is 1999 / (3291 +1999), which is approximately 38%

[hc4361]

Thanks again.

[nescio]

I see The Builder and knowabit beat me to it!

[Baldric]

Oops, misread the Question,
Knowabit is correct
It should be 37.788% of total usage

[Tilly2]

I think I read this wrong. Your total 24 hour usage is 5290, is it?
If sothen your night time usage is 37.7%

[Baldric]

Tilly, I used my head, and grabbed the calculator, shame I misread the question though!

[Tilly2]

We both did, Baldric.

[Tilly2]

But, at night you use use 60% of what you use in the daytime. You use 40% more during the day.

[Peter Pedant]

Baldric do you really do three places of decimals in your head
( even if you do start off with the wrong fraction in the first place ? )

[factor-fiction]

It's usually worth doing an estimate first using rounded numbers just to get a feel of what the answer should look like. In this case the total number of units is roughly 5000 and 2000 of these are at night rate. Then 2000/5000 is like 20 out of every 50 which is like 40 out of 100- so 40%.