Answer: [tex]\dfrac{49}{99}[/tex]
Step-by-step explanation:
There are 61 boys --> 38 girls
A) 19 chose football: 5 are girls --> 14 are boys
B) 38 girls: 28 chose running, 5 chose football --> 5 girls chose tennis
C) 31 students chose tennis: 5 are girls --> 26 are boys.
D) 61 boys: 14 chose football, 26 chose tennis --> 21 boys chose running.
[tex]\large\boxed{\begin{array}{l|cc||c}&\underline{Boys}&\underline{Girls}&\underline{Total}\\Football&14&5&19\\Tennis&26&5&31\\\underline{Running}&\underline{\quad 21\quad}&\underline{\quad 28\quad}&\underline{\quad 29\quad}\\Total&61&38&99\end{array}}[/tex]
Total running = 21 boys + 28 girls = 49
Total students = 99
[tex]\dfrac{\text{Total running}}{\text{Total students}}=\large\boxed{\dfrac{49}{99}}[/tex]