Onethird of a nuber added to fourfifth of itself equals to 20 find the number

(1/3)n + (4/5)n = 20

(5/15)n + (12/15)n = 20
(17/15)n = 20
n = 20 / (17/15)
n = 20 * (15/17)
n = 300/17
n = 17.65