Questions:- How many pink beads
 are there in the bag ?
Given :- 
- 5 beads are orange 
- 3 beads are purple
- except orange and purple all are pink 
- ⅗ is the probability of the pink beads 
To find :- Number of pink beads.
Explanation:- 
Sum of the given orange and purple beads ->
 5+3=8 beads .
sum of all the probabilities is equal to 1
so :- 
1 = probality of orange and purple+probality of pink 
Probality of orange and purple = 
 1 - probality of pink
Probality of orange and purple = 1-⅗

we know :- 

Putting the values in equation:- 

Number of pink beads = total number of beads - numbe of orange and purple beads 
Pink beads = 20 -5-3
Pink beads = 20 -8 = 12 beads 
Answer = Pink = 12 beads