IP addresses are composed of four decimal numbers separated by periods. If I had to guess, someone was asking you to look at either 172.24.43.226 or 172.24.43.227 .
"172.24.43.226/27" means "the subnet starting at 172.24.43.226 with a mask of 27 bits (255.255.255.224)". It doesn't mean "172.24.43.226 or 172.24.43.227". There error means that given a mask of 27 bits, 172.24.43.226 is not the start of a subnet.