Answer:
A = 112 , C = 85 , B = 90
Step-by-step explanation:
A + B + C = 287
A + C = 197
A + B = 202
C = 197 - A
B = 202 - A
A + 202 - A + 197 - A = 287
A = 112
C = 85
B = 90
x = liters of 40% solution
y = liters of 70% solution
Gabe needs 30 liters, so
x + y = 30
Each liter of 40% solution contributes 0.4x liter of acid; each liter of 70% solution contributes 0.7y liter of acid. Gabe needs a solution with concentration 60%, which from 30 liters amounts to a net volume of 0.6*30 = 18 liters of acid. So
0.4x + 0.7y = 18
Solve the system however you like. By substitution, we have
y = 30 - x
0.4x + 0.7(30 - x) = 18
0.4x + 21 - 0.7x = 18
3 = 0.3x
==> x = 10 ==> y = 20
Answer:
x = 87
Step-by-step explanation:
An exterior angle of a triangle is equal to the sum of the opposite interior angles.
Label the angles left and right of the right angle as "a" and "b". Then we have ...
a + b + 90 = 180
b = 90 - a . . . . subtract (90+a)
And we have a relation with the left exterior angle:
72 + a = 138
a = 138 -72 = 66 . . . . subtract 72
__
b = 90 -66 = 24 . . . . from above
And another relation with the right exterior angle:
(180 -x) +b = 117 . . . . . . the interior angle with "b" is the supplement of x
204 -x = 117 . . . . . . . . . substitute 24 for b
204 -117 = x = 87 . . . . add x-117
The measure of the angle marked x° is 87°.
Answer:
7x+18
Step-by-step explanation:
Answer:
number 2 and 4
Step-by-step explanation:
