With amounts measured in gallons, let
x = amount of 65% antifreeze
y = amount of 90% antifreeze
1 gal of the 65% brand contains 0.65 gal of pure antifreeze; x gal would contain 0.65x gal. Similarly, y gal of the 90% brand contains 0.90y gal of pure antifreeze.
To obtain 120 gal of 80% antifreeze solution (which contains 0.80•120 = 96 gal of pure antifreeze), we must have
x + y = 120 … … … … … [total volume of antifreeze solution]
0.65x + 0.90y = 96 … [total volume of pure antifreeze]
Solve the first equation for y :
y = 120 - x
Substitute this into the second equation and solve for x :
0.65x + 0.90 (120 - x) = 96
0.65x + 108 - 0.90x = 96
0.25x = 12
x = 48
Solve for y :
y = 120 - 48
y = 72
Answer:
1. real number, irrational number
2. rational number, real number
To estimate the quotient, we first round off the divisor and the dividend to the nearest tens, hundreds, or thousands and then divide the rounded numbers. In a division sum, when the divisor is made up of 2 digits or more than 2 digits, it helps if we first estimate the quotient and then try to find the actual number.
Answer:
a) 137.9°
b) 12.2° (please refer to explanation because I didn't know what to round to)
Step-by-step explanation:
1a) A supplementary angle will equal 180°, so you must subtract 42.1 from 180
180-42.1 = 137.9
1b) A complementary angle will equal 90°, so you need to use the expression given and add an x for the other part of 90°
8x-20+x = 90
9x-20=90
9x=110
x=12.2
A) x – 7 = -7(6y + 5)
x – 7 = -42y + -35
x – 7 + 35 = -42y
x + 28 = -42y
y = (1/42)x – 14/21
c) y – 7 = 7(x + 5)
y – 7 = 7x + 35
y = 7x + 42
b) y – 7 = -7(x + 5)
y – 7 = -7x -35
y = -7x – 28
d) y + 7 = 7(x + 5)
y + 7 = 7x + 35
y = 7x + 28
