If Sally has x books that are 2 pounds then her x books weights a total of 2x lbs.
8 books of 3 lbs weights 8*3=24lbs
All them add up to 62, therefore we can conclude to the equation :
2x+24=62
or we can simplify to
2x=38
or even
x=19
It's a bit tedious, but it's just a bunch of factoring and manipulation.
Answer:
90, 45
Step-by-step explanation:
0.3x = 27
x = 90
50% of 90 = 45
Answer:
maths question
................................................... hope it is helpful to you
Answer:
decreasing at 390 miles per hour
Step-by-step explanation:
Airplane A's distance in miles to the airport can be written as ...
a = 30 -250t . . . . . where t is in hours
Likewise, airplane B's distance to the airport can be written as ...
b = 40 -300t
The distance (d) between the airplanes can be found using the Pythagorean theorem:
d^2 = a^2 + b^2
Differentiating with respect to time, we have ...
2d·d' = 2a·a' +2b·b'
d' = (a·a' +b·b')/d
__
To find a numerical value of this, we need to find the values of its variables at t=0.
a = 30 -250·0 = 30
a' = -250
b = 40 -300·0 = 40
b' = -300
d = √(a²+b²) = √(900+1600) = 50
Then ...
d' = (30(-250) +40(-300))/50 = -19500/50 = -390
The distance between the airplanes is decreasing at 390 miles per hour.
