A laboratory must prepare 200.0 g of a sulfuric acid solution that is 25.0 % H2SO4 by mass using stock solutions that are 5.0 %, 20.0 %, and 35.0 % H2SO4 by mass. Safety guidelines require that the mass of the 5.0 % solution be exactly one-third of the mass of the 35.0 % solution. What mass of the 35.0 % stock solution should be used?
a) 66.7g
b) 1.00×102g
c) 1.12×102g
d) 150g