Answer:
1. 11cm
2.3meters 20cm
Explanation:
1. Avinash is 1.8m tall
 Arun is 191cm tall
1.8m to cm= 180cm
Difference in their heights = (191-180)cm
 =11cm.
2. Total length of 6ropes in cm= (19m×100)+20cm
 =(1900+20)cm 
 =1920cm
Length of 1 rope = 1920cm÷6 ropes
 =320cm
 To meters = 320÷100
 =3m20cm.