Mass/mass percent concentration means the mass of the solute/mass of the solution times 100. You know both the mass of the solute (0.870 g protein) and the mass of the solution (10.279 g solution). So divide and multiply your result by 100. (0.870 / 10.279 * 100)
That easy..............<span>21 one is your technical answer according to todays rules but scientist used to think it was only 20 so 20 would be your answer</span>