Answer:
Fred used 8 roses to make the bouquet.
Step-by-step explanation:
Let 'x' roses be used to make a bouquet.
Given:
Cost of carnations = $5.25
Cost of 1 rose = $1.68
Total cost of the bouquet = $18.69
Cost of 1 rose = $1.68
Therefore, using unitary method, the cost of 'x' roses is given as:
Cost of 'x' roses = [tex]1.68x[/tex]
Now, as per question:
Cost of carnations + Cost of 'x' roses = Total cost of the bouquet
[tex]5.25+1.68x=18.69\\\\1.68x=18.69-5.25\\\\1.68x=13.44\\\\x=\frac{13.44}{1.68}\\\\x=8[/tex]
Therefore, Fred used 8 roses to make the bouquet.
