Answer:
45?
9 marbles x 5 (four of her friends plus jake)
Step-by-step explanation:
We know that
The formula for combinations is
C=n!/[(n-r)!*r!]
where
n is the total number of objects you choose from
r is the number that you choose to arrange
in this problem
n=15 students
r=4 students
C=15!/[(15-4)!*4!]-----> C=15!/[11!*4!]---> (15*14*13*12*11!)/(11!*4*3*2*1)
C=(15*14*13*12)/(24)----->C=1365
the answer is
1365
P(x) =9x +30
the tips are a flat rate so it’s a constant 30 while the 9 per hour is dependent on the hours worked which is why it is attached to x as a coefficient
A=1/10, b=1/12, c=1/15 (these are the rates for each worker...)
1.)
2(1/10)+4(1/12)+t/15=1
1/5+1/3+t/15=1
(3+5+t)/15=1
3+5+t=15
8+t=15
t=7
So it would take c 7 hours to finish the job.
2.)
1/40-1/60
(3-2)/120
1/120
The drain rate is 1/60. So you will need to find t when the tank is empty, while starting at 2/3 capacity...
2/3-t/60=0
(40-t)/60=0
40-t=0
t=40
It would take 40 minutes to empty the tank when it is 2/3 full.
Answer: a/c = 1
a/b = 1/2 => a = 1/2 .b
b/c = 2 => c = 1/2 .b
=> a/c = (1/2.b)/(1/2.b) = 1
Step-by-step explanation:
