Please help me with this problem converstion 0.04 ug/ul to ng/mL

My answer is: 0.04 ug/ul = 40,000,000 ng/mL is this correct?

That is correct

I don't agree with either answer.

https://www.google.com/search?q=0.04+micrograms%2Fmicroliter+to+nanograms%2FmL&ie=utf-8&oe=utf-8

To convert from micrograms per microliter (ug/ul) to nanograms per milliliter (ng/mL), you need to remember that:

1 microgram (ug) = 1000 nanograms (ng)
1 microliter (ul) = 1000 milliliters (mL)

Therefore, the conversion factor needed is 1000, as you're moving from ug (10^-6) to ng (10^-9), and ul (10^-6) to mL (10^-3).

To convert 0.04 ug/ul to ng/mL, multiply by the conversion factor:

0.04 ug/ul * 1000 ng/ug * 1000 mL/ul = 40,000 ng/mL

Therefore, the correct answer is 40,000 ng/mL.