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
Answer:
3.81972
Step-by-step explanation:
Use property of proportion:
miles time (hs)
90 2.25
x 1
x = 90 ÷ 2.25
x = 40 miles
D = # of dimes
n= # of nickles
d + n = 34 so d = 34 - n
.10d + .05n = 2.05
substitute d = 34 - n into .10d + .05n = 2.05
.10d + .05n = 2.05
.10( 34 - n) + .05n = 2.05
3.4 - .1n + .05n = 2.05
-.05n = -1.35
n = 27
d = 34 - n
d = 34 - 27
d = 7
answer
<span>she received 7 dimes and 27 nickels</span>