There are two memory slots -- your specific system could have one or two depending on how it was built. You can look up the original configuration at support.dell.com using the service tag, or simply remove the base cover and check visually.  
Hi. How much RAM sticks does Inspiron 15 7567 have? These are the specs, if it affects, It's 7th gen I7 CPU, GTX 1050TI, 128GB SSD (Boot)+ 1TB HDD(Storage). Because I saw some people on YouTube have 1 stick of RAM, another people have 2 sticks. Thanks.
Dell Inspiron 15 7567 RAMs