Neelam is pouring sand into a clear box to make sand art. The box is a right rectangular prism, and the base of the box is a right rectangular prism, and the base of the box is 7 in. by 2 1/2 in. She pours in red sand until the volume of the sand is 26 1/4 in.3. Then she pours in blue sand. Now the volume of the sand is 43 3/4 in.3. How much does the level of the sand rise when Neelam adds the blue sand?​