Answer:
15 races
Step-by-step explanation:
The team has competed in 45 and has won 30. So the success rate is:
Success rate is:
[tex]Sccess\ rate=r= \frac{30}{45}*100\\ =66.7\ percent[/tex]
We have to find the number of races the team needs to win for 75% success rate
Which means that
[tex]r = \frac{30+x}{45+x} = 0.75\\[/tex]
We have to solve the equation for x
[tex]\frac{30+x}{45+x}=0.75\\ 30+x = 0.75(45+x)\\30+x=33.75+0.75x\\x-0.75x=33.75-30\\0.25x=3.75\\x=\frac{3.75}{0.25}\\ x=15[/tex]
The team needs to win 15 races to get 75% success rate ..
