Question

how many envelopes of size 20cm×30cm be made from a rectangular sheet of paper measuring 5m×3m

Answer 1

Area of sheet=5*3m^2
=15m^2 =150000cm^2
Area of envelope=20*30cm^2
=600cm^2
No. of envelopes made by rectangular sheet=150000cm^2/600cm^2
=250

Answer 2

Let the envelopes be n

n × 20cm × 30cm = 500cm × 300cm


$n = \frac{500 \times 300}{20 \times 30}$

n = 250


So,

250 envelopes can be made .