What is the composition of 21 g NaCl in 500 ml solution (density 1.12 g/ml) in % (w/w)?

Question

1. 0.375%

2. 21.25%

3. 3.75%

4. 4.75%

5. 2.125%

Answer 1

answer is % (w/w)
=
21g/(500ml x 1.12 g/ml)
=
21/560
=
3.75%