Answer:
The number of hours Jackie worked = 80hours
Step-by-step explanation:
Last summer:
Jackie made $960
Rachel made $960
let number of hours Jackie worked = x
Rachel worked 16 hours more than Jackie:
Number of hours Rachel worked = x + 16
if Jackie earned $y per hour
Rachel earned $2 less per hour = y-2
Jackie: 960 = x × y = xy
Rachel: 960 = (x+16)(y-2)
960 = xy -2x +16y -32
recall xy = 960, insert the value for xy
960 = 960 - 2x +16y -32
- 2x +16y -32 = 0
2x -16y = -32
x-8y = -16
x = 8y-16
recall xy = 960, insert the expression for x
(8y-16)y = 960
8y² -16y = 960
y² -2y - 120 = 0
y²+10y-12y -120 = 0
y(y+10) -12(y+10) = 0
(y-12) = 0 or (y+10) = 0
y = 12 or -10
since y can't be negative, y = 12
x = 8y-16
x = 8(12) -16 = 80
The number of hours Jackie worked = x = 80 hours
Answer:
1) The store selling for 1.1 per 3 lbs
2) $6.24
Step-by-step explanation:
1)
1.1/3 = 0.37
0.78/2 = 0.39
0.37 is cheaper so it's a better deal
2)
2/5/9 solved will be 0.4 repeating as a decimal, & 4/9 as a fraction
So first you distribute the negative to the 6x and 13 which will flip the sign of both of them to -6x and -13 so take away the parentheses and the equation is now 7x-6x-13. You combine the x’s and you get 1x-13 or x-13
The percentage of the radioactive isotope left is 25.0000%.
<h3>What is the half life?</h3>
The half life of a radioactive isotope is the time that will elapse before only half of the number of original isotopes will remain.
Now;
We are told that;
Half life (t1/2) = 55 days
Time taken (t) = 115 days
Ratio of isotope remaining = N/No
Thus;
N/No = (1/2)^t/t1/2
N/No = (1/2)^115/55
N/No = (1/2)^2
N/No =1/4
Hence, the percentage = 1/4 * 100/1 = 25.0000%
Learn more about half life of an isotope:brainly.com/question/16387602
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