Rearrangement of Formulae, Algebra. Please help.

[quote="CPlusHris"][input]4.3*10^-3=10.2(sqrt(2y*(147.83-51.9[/input] Estimate the following of y correct to one significant figure without using a calculator.

I have tried several times to try and solve this. I ended up with 0.016 as an estimate using the following method.

1. Round off: 4.0* 10^-3=10(sqrt(2y*(150-50)
2. Put 4.3*^-3 into standard form: 0.0043

Working out
0.0040=10(sqrt(2y*(150-50)

0.0040=10(sqrt(2y*100)

0. 00040=(sqrt(2y*100)

0.00000016=2y*100

0.0000000008

8 * 10^(-10)

Just a couple of little errors can make a big difference!

The actual answer is 9 * 10^(-10) Correct to 1 significant figure.

So your answer (and mine) does not quite have the accuracy that you were asked for.
But I still think that it is a sensible estimate.

Oh, now I see where I went wrong, instead of dividing 0.0040 by 10, I multiplied it.
Thanks for the help, much appreciated.

This question had me stumped for at least half an hour.

You are very welcome Chris (I assume your name is Chris?)
It can be very frustrating when you get stuck on a question. I know this.