ANSWER :
48
EXPLANATION :
The length of the major axis (2a) is 50 and the length of the minor axis (2b) is 14
So :
[tex]\begin{gathered} 2a=50 \\ a=25 \\ \\ 2b=14 \\ b=7 \end{gathered}[/tex]The distance between the foci is 2c, and the formula of c is :
[tex]c^2=a^2-b^2[/tex]Using the formula above :
[tex]\begin{gathered} c^2=25^2-7^2 \\ c^2=576 \\ c=\sqrt{576} \\ c=24 \end{gathered}[/tex]Then the distance of the foci is 2c = 2(24) = 48
