We know that 13/30 of flowers are roses, and 2/5 are orchids. These two flowers make
[tex]\dfrac{13}{30}+\dfrac{2}{5}=\dfrac{13}{30}+\dfrac{12}{30}=\dfrac{25}{30}[/tex]
of the total number of flowers, implying that gladioli represent the remaining [tex]1-\dfrac{25}{30}=\dfrac{30}{30}-\dfrac{25}{30}=\dfrac{5}{30}=\dfrac{1}{6}[/tex]
So, if gladioli represent 1/6 of the total, and they are 7, then the total will be 6*7=42 flowers.
