We have 55% and 80% antifreeze. We need 90 gallons of 75%.
F - 55% and E - 80%
A) F + E = 90
B) .55 F + .80 E = 67.50 (which is .75 * 90) Multiplying A) by -.55
A) -.55 F -.55 E = -49.50 (which is -.55 * 90) then adding A) & B)
.25 E = 18
E = 72 gallons of 80% and
F = 18 gallons of 55%
********* DOUBLE CHECK ******************
72 * .80 = 57.60 and 18 * .55 = 9.90
57.60 + 9.90 = 67.50 gallons of antifreeze and we have 90 total gallons
(67.50 / 90) * 100 = 75% correct!
Source: 1728.com/mixture.htm
|----------------------------------120 m ------------------------------|
|--------------|--------------|--------------|--------------|--------------|
P Q R
Distance from P to R = 120m
120 ÷ 5 = 24m
The distance from Q to R is 24m.
<span>When creating a subset of 5 elements from 7 elements, order should not matter. Therefore, we use the combination formula over the permutation formula.
The combination formula given n elements total and r elements used is n! / [r!*(n-r)!]. Substituting 7 for n and 5 for r, we get:
7! / (5!*2!) = 7*6 / 2 = 21
21 subsets can be created</span>
9514 1404 393
Answer:
see below
Step-by-step explanation:
It is easiest to compare the equations when they are written in the same form.
The first set can be written in slope-intercept form.
y = 2x +7
y = 2x +7 . . . . add 2x
These equations are <em>identical</em>, so have infinitely many solutions.
__
The second set can be written in standard form.
y +4x = -5
y +4x = -10
These equations <em>differ only in their constant</em>, so have no solutions.
__
The third set is already written in slope-intercept form. The equations have <em>different slopes</em>, so have exactly one solution.
Step-by-step explanation:
Given
Hope it will help :)
