We have different densities for different phone sizes as it is given in google developer website
36x36 (0.75x) for low-density
48x48 (1.0x baseline) for medium-density
72x72 (1.5x) for high-density
96x96 (2.0x) for extra-high-density
180x180 (3.0x) for extra-extra-high-density
192x192 (4.0x) for extra-extra-extra-high-density
Now if i have an image of size 60x60 for mdpi phone then i can calculate all other sizes by multiplying 60 by (1.5, 2.0, 3.0 or 4.0). Then how do i calculate the size of images for tablet? If i can put it simply what should i tell graphic designer to provide me if i am going to build a new app that will support both phone and tablet?