Answer:
The least number of stamps required is [tex]9[/tex]
Step-by-step explanation:
Let the number of [tex]3[/tex] cent stamps be [tex]x[/tex] and [tex]4[/tex] cent stamps be [tex]y[/tex]
We have
[tex]3x+4y=33[/tex]
The minimum number is obtained when more [tex]4[/tex] cent stamps are used
Here [tex]y[/tex] cannot be greater than [tex]8[/tex] since [tex]\frac{33}{4} <9[/tex]
Substitute [tex]y=8[/tex]
[tex]3x+4\times 8=33\\\\3x=1\\\\x=\frac{1}{3}[/tex]
Not possible since [tex]x[/tex] is not a fraction
Substitute [tex]y=7[/tex]
[tex]3x+4\times 7=33\\\\3x=5\\\\x=\frac{5}{3}[/tex]
Not possible since [tex]x[/tex] is not a fraction
Substitute [tex]y=6[/tex]
[tex]3x+4\times 6=33\\\\3x=9\\\\x=\frac{9}{3}\\\\=3[/tex]
Possible
Hence minimum number of stamps is
[tex]=x+y\\\\=3+6\\\\=9[/tex]
