Well she has $10 and each spinach is $3 so she can not but no more than 3.
You solve this by using google.com or YouTube.com
Or just pay attention in class to get this.
Hey there!!
The area for the volume of a cube -
s³ , s = side
volume = 216
s³ = 216
s = ∛216
s = 6
The required answer is 6
Hope my answer helps!