Question 957921
N=amount of 9%; F=amount of 14%
N+F=260ml
N=260ml-F
0.09N+0.14F=0.13(260ml) Substitute for N.
0.09(260ml-F)+0.14F=33.8ml
23.4ml-0.09F+0.14F=33.8ml Subtract 23.4ml from each side.
0.05F=10.4ml Divide each side by 0.05
F=208ml ANSWER 1 She should use 208 ml of the 14% brand.
N=260ml-F=260ml-208ml=52ml ANSWER 2: She should use 52ml of the 9% brand.
CHECK:
0.09N+0.14F=0.13(260ml)
0.09(52ml)+0.14(208ml)=0.13(260ml)
4.68ml+29.12ml=33.8
33.8ml=33.8ml