Hello here is a solution
look graph :
the curve : color blue
the first tangent : y = 0.13x +1.87 color Pink
the second tangent : y = 1.88 x +0.14 color green
Let x and y be the 2 parts of 15 ==> x + y=15 (given)
Reciprocal of x and y ==> 1/x +1/y ==> 1/x + 1/y = 3/10 (given)
Let's solve 1/x + 1/y = 3/10 . Common denominator = 10.x.y (reduce to same denominator)
==> (10y+10x)/10xy = 3xy/10xy ==> 10x+10y =3xy
But x+y = 15 , then 10x+10y =150 ==> 150=3xy and xy = 50
Now we have the sum S of the 2 parts that is S = 15 and
their Product = xy =50
Let's use the quadratic equation for S and P==> X² -SX +P =0
Or X² - 15X + 50=0, Solve for X & you will find:
The 1st part of 15 is 10 & the 2nd part is 5
3 boxes of computer diskettes at $8.99 per box = (3 * 8.99 = 26.97 )
2 packages of pens at $ 2.50 per package = (2 * 2.50 = 5.00 )
6 boxes of paper at $ 22.95 per box = (6 * 22.95 = 137.70)
1 printer ribbon at $25 each. = (1 * 25 = 25)
Add up (26.97+5.00+137.70+25 ) and the answer is = 194.67
Finding the greatest common factor ( or G C F ):
G C F is the largest number that divides evenly into all the numbers.
270 : 90 = 3
360 : 90 = 4
G C F ( 270, 360 ) = 90