If the backpack (b) contains only textbooks (t) and notebooks (n), the total weight of the backpack is:
b+t+n
but notebooks are 4 pounds, so actually:
b+t+4
also, the backpack weights 2 pounds, so the total weight is:
2+t+4 =t+6
now, "Seventy percent of
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the total weight is textbooks. ", this means that
t=70%(t+6) - this equation can be used to determine the weight of the textbooks!
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Combined work problems
job/time + job/time = job/ total time
(1/80) + (1/100) = 1/T
(10/800) + (8/800) = 1/T
18/800 = 1/T
800/18 = T
44.44 hrs = T
Answer:
The standard form of a circle is (x-h)^2 + (y-k)^2 = r^2 with (h,k) being the center of the circle and r being the radius. In this case the circle's equation in standard form is (x-2)^2 + (y+3)^2 = 18. Knowing this it's easy to see that the center of the circle (h,k) is (2,-3). Finally the radius is
or in simplified terms, 3
Step-by-step explanation: