Maury = 120/10 (12 calls/hour)
Tyra = 120/8 (15 calls/hour)
Together they are 27 calls per hour.
120 / 27 = 4.4444444444
So it'd take them 4.44444444 (recurring) hours to make 120 calls.
With cross multiplication you can find that they are the same. In both equations, x would be 100.
Step-by-step explanation:
(9x2 - 2x +7) +(4x2+7x +2)
9x2 - 2x +7 +4x2 +7x +2
13x2 +5x +9
Solve
hmmm
half life
well, 120 to 60 is half
60=120e^(-0.00043t)
solve for t
divide both sides by 120
1/2=e^(-0.00043t)
take ln of both sides
ln(1/2)=-0.00043t
divide both sides by -0.00043
ln(1/2)/-0.00043=t
t≈1611.97 years
about 1612 years
First year $2000
1- $2200
2- $ 2420
3- $2662
4- $2,928.2
good luck
