Number of hockey cards in Nick's album = 700
Number of hockey cards in each page of the album = 7
Number of pages in Nick's album :
[tex] = \tt \frac{700}{7} [/tex]
[tex] = \tt100[/tex]
▪︎Thus, the number of pages in Nick's album = 100
Percentage of album that is empty = 72%
Number of pages in the album that is empty :
[tex] = \tt 72\% \: \: of \: \: 100[/tex]
[tex] =\tt \frac{72}{100} \times 100[/tex]
[tex] = \tt \frac{72 \times100}{100} [/tex]
[tex] =\tt \frac{7200}{100} [/tex]
[tex] \color{plum}= \tt72 \: pages[/tex]
▪︎Thus, the number of empty pages in the album = 72
Number of pages in the album that are filled :
[tex] =\tt 100 - 72[/tex]
[tex]\color{plum} = \tt28 \: pages[/tex]
Number of pages filled with hockey cards = 28