Answer:
She used 2 17/20 strings of grey beads
Explanation:
Here, we want to know the number of grey beads used
To calculate this, we simply add up the black beads number with the number of grey beads
Mathematically, that will be;
1 1/20 + 1 4/5
= 21/20 + 9/5
= (21 + 36)/20
= 57/20 = 2 17/20