Let x be the whole amount.
1) 8% of x is 72cm
[tex]0.08 \times x = 72 \\ x = 72 \div 0.08 \\ x = 900cm[/tex]
2) 0.6% of x is 18g
[tex]0.006 \times x = 18 \\ x = 18 \div 0.006 \\ x = 3000g[/tex]
3) 120% of x is 24m
[tex]1.2 \times x = 24 \\ x = 24 \div 1.2 \\ x = 20m[/tex]
