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
Step-by-step explanation:
after I answered the other one(s), you should be really able to do this yourself.
it is precisely the same method and formula just with different numbers.
what's the problem now ?
y = -16x² + 247x + 141
we assume, the ground is at 0 ft.
so, we need to solve
0 = -16x² + 247 x + 141
the general solution for such quadratic equations is
x = (-b ± sqrt(b² - 4ac))/(2a)
in our case
a = -16
b = 247
c = 141
x = (-247 ± sqrt(247² - 4×-16×141))/(2×-16) =
= (-247 ± sqrt(61009 + 9024))/-32 =
= (-247 ± sqrt(70033))/-32
x1 = (-247 + 264.6374879...)/-32 = -0.551171497... s
x2 = (-247 - 264.6374879...)/-32 = 15.9886715... s
again, the negative solution for time did not make any sense, so, x2 is our solution.
the rocket will hit the ground after about 15.99 seconds.
Answer:
jojo siwas forehead
Step-by-step explanation:
Answer:
0.02020202... = 2/99.
Step-by-step explanation:
This is a repetitive decimal number . It can be converted to a rational number:
.020202, * 100 = 2.0202...
.020202 * 1 = 0 0202....
Subtract
0.020202 * 99 = 2
So 0.020202.. = 2/99.
425 cm. The ratio is 17 : x is equal to 2cm : 50cm. You use cross multiplication to solve. 17 times 50 = 2 times x.
850 = 2x
425 = x
