For problems such as this, it can be handy to remember that
.. 1/(1/a +1/b) = ab/(a +b)
The time required to do a job is the inverse of the rate at which the job is done. Rates are added when people work together (in math problems, not in real life).
(2:44)*(3:14)/(2:44 +3:14) = 1:28:52.3
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2:44 = 41/15 hours = 82/30 hours
3:14 = 97/30 hours
Using the formula above, we have a "working together" time of
.. (82/30)*(97/30)/(82/30 +97/30) = 82*97/(30*179) = 3977/2685 . . . hours
.. = 1 hour 28 156/179 minutes
.. = 1 hour 28 minutes 52 52/179 seconds
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Learn to use the fraction functions on your calculator. They can be very helpful.
You want to multiply together the number of possible choices for each digit in the code.
0-9 is ten possible numbers, since repetitions are allowed (example code 2,2,2,2) there are ten possible choices per digit in the code.
10*10*10*10 = 10,000 four digit coded possible
Answer:
a) 50,000 + 2x > 70,000
Step-by-step explanation:
Mrs. Lobo has an annual salary of $50000 per year plus 4% commission on her sales.
If she makes $y commission from sales, Mrs Lobo total income per year is:
$50000 + $y.
She makes 4% commission on her sales of share with the average price of a share = $50
Average commission from sales = 4% × $50 = 0.04 × 50 = $2
If she sales x shares in a year, her commission would be $2x for the year. Therefore her total income for that year would be:
50000 + 2x
The amount of shares Mrs Lobbo must sell to make an annual income of at
least $70,000 is given by the inequality:
50,000 + 2x > 70,000
So what we do is
area that remains=total area-triangle area that was cut out
we need to find 2 things
total area
triangle area
total area=rectange=base times height
area=(3x+4) times (2x+3)
FOIL or distribute
6x^2+8x+9x+12=6x^2+17x+12
triangle area=1/2 times base times height
triangle area=1/2 times (2x+2) times (x-2)=
(x+2) times (x-2)=x^2+2x-2x-4=x^2-4
so
total area=6x^2+17x+12
triangle area=x^2-4
subtract
area that remains=total area-triangle area that was cut out
area that remains=6x^2+17x+12-(x^2-4)=
6x^2+17x+12-x^2+4=
6x^2-x^2+17x+12+4=
5x^2+17x+16
area that remains is 5x^2+17x+16
