Answer:
The probability that exactly 5 are unable to complete the race is 0.1047
Step-by-step explanation:
We are given that 25% of all who enters a race do not complete.
30 have entered.
what is the probability that exactly 5 are unable to complete the race?
So, We will use binomial
Formula : 
p is the probability of success i.e. 25% = 0.25
q is the probability of failure = 1- p = 1-0.25 = 0.75
We are supposed to find the probability that exactly 5 are unable to complete the race
n = 30
r = 5



Hence the probability that exactly 5 are unable to complete the race is 0.1047
1. 5x + 6 = 2 + 3x
-3x. - 3x
-------------------------
2x + 6 = 2
- 6. - 6
-------------------------
2x = -4
---- -----
2. 2
x = -2
2. 2(6 -2y) = -1(4y-9)
12 -4y = -4y + 9
+4y. +4y
----------------------------
.12 /=\ 9
No solution
3. 2z-6 = 2(z+2) + 10
2z -6 = 2z + 4 + 10
2z -6 = 2z +14
-2z. -2z
-6 /=\ 14
No solution.