Answer:
[tex]Budget = 3 b[/tex]
Step-by-step explanation:
Given
[tex]Budget = \$30[/tex]
[tex]Cost\ of\ box (b) = \$10[/tex]
Required
Represent as an equation;
[tex]Budget = \$30[/tex]
Expand the above
[tex]Budget = 3 * \$10[/tex]
Recall that b = $10 ----given
[tex]Budget = 3 * \$10[/tex] becomes
[tex]Budget = 3 * b[/tex]
[tex]Budget = 3 b[/tex]