Question 261477
This the same as a coin problem
nickels are worth 5 cents 
Dimes are 10 cents

What do we know? 
Insects have 6 legs
Spiders (arachnids) have 8 legs
There are a total of 54 legs
and there are a total of 8 bugs
a+i=8
6i+8a=54
a=3
i=5