Answer:
If there is no interest then $9000
Step-by-step explanation:
-200t represents paying back 200 dollars a month
9000 represents original debt (including interest)
We have 60 gallons of 20% antifreeze.
How much 70% antifreeze do we add to get 60% antifreeze?
We'll make "x" the gallons of 70% we must add.
.20 * 60 + .70 x = .60 * (60 + x)
12 + .70x = 36 + .60x
.10x = 24
x = 240 gallons of 70% antifreeze.
Source
1728.com/mixture.htm (see example B)
Answer:
5 hours 22 minutes
Step-by-step explanation:
Let us represent the number of hours that Jeri worked as: h
Jeri's lawn service charges an initial fee of $4.50 plus $3 an hour
= $4.50 + $3 × h
= $4.50 + 3h
If she is asked to start before 7 a.m. Jeri charges 1.5 times the regular amount.
= 1.5 × ($4.50 + 3h)
If she made $29.25 on a job that began at 5 am, how many hours did Jeri work?
Hence, we have the final equation;
= 1.5 × ($4.50 + 3h) = $29.25
= 6.75 + 4.5h = 29.25
Collect like terms
= 4.5h = 29.25 - 6.75
4.5h = 22.5
h = 22.5/4.5
h = 5.3571428571
Approximately= 5.36 hours
1 hour = 60 minutes
0.36 hour =
60 × 0.36
= 21.6 minutes
Approximately ≈ 22 minutes
Therefore, Jeri worked for 5 hours 22 minutes
Answer:
22.38 g of silicone-32 will be present in 300 years.
Step-by-step explanation:
A radioactive half-life refers to the amount of time it takes for half of the original isotope to decay and its given by
where,
= quantity of the substance remaining
= initial quantity of the substance
= time elapsed
= half life of the substance
From the information given we know:
- The initial quantity of silicone-32 is 30 g.
- The time elapsed is 300 years.
- The half life of silicone-32 is 710 years.
So, to find the quantity of silicone-32 remaining we apply the above equation
22.38 g of silicone-32 will be present in 300 years.
