Answer:
Before submerged 150ml
After submerged: 180ml
rock volume: [tex]180 - 150 = 30[/tex]
formula for density:
[tex] \frac{mass}{volume} = 5.38 [/tex]
[tex] \frac{175}{30} = 5.38 [/tex]
THE ANSWER IS b
prettty sure this is wrong but eh :/ probably correct
