A decrease in the ratio 4:5 implies that :
New quantity:Old quantity = 4:5
Let the new quantity be [tex] \bf \: x[/tex]
[tex] \bf∴ x : 40 = 4:5[/tex]
[tex] = > \bf \frac{x}{40} = \frac{4}{5} [/tex]
[tex] \bf = > 40 \times \frac{x}{40} = 40 \times \frac{4}{5} [/tex]
[tex] \bf = > x = 8 \times 4[/tex]
[tex] \bf = > x = 32[/tex]
So, the new quantity is 32
