For this case we propose a system of equations. We have to:
x: Let the variable that represents the number of dimes
y: Let the variable that represents the number of quaters
We know that:
One dime equals 10 cents, $0.10
A quater equals 0.25 cents, $0.25
According to the statement we have:

We multiply the first equation by -0.10:

We have the following equivalent system:

We add the equations:

Approximately 3 quater coins

And two dimes
Answer:
3 quater
2 dimes
$20.00 - $15.24 = $4.76 in change. I'd say review decimal subtraction which you should have learned in fourth or fifth grade. Hope this helps!
Use pothomath that app is good
For math
Solution: We are given:
μ=3.1,σ=0.5,n=50
We have to find P(Mean <2.9)
We need to first find the z score
z= (xbar-μ)/(σ/sqrt(n))
=(2.9-3.1)/(0.5/sqrt(50))
=(-0.2)/0.0707
=-2.83
Now we have to find P(z<-2.83)
Using the standard normal table, we have:
P(z<-2.83)=0.0023
Therefore the probability of the sample mean being less the 2.9 inches is 0.0023