Answer:
1. 424
2.471
3.512
Step-by-step explanation:
1. 10×12+8×10+8×13+8×15
=120+80+104+120
=424
2. 5×24+9×24+9×15+9×15
=120+216+135
=471
3. 24×16+2×24+2×20+2×20
=384+48+40+40
=512

notice, that, pure juice is 100% juice, dohhh, thus 100/100 = 1.00
50% is 50/100 or 0.50 in decimal format
so..... whatever those two quantities amount to, that is, the 50% and pure juice, or (4)(0.50) + (x)(1.00)
they will equal the mixture desired 60% juice, or 0.60, namely (4+x)(0.60)
thus (4)(0.50) + (x)(1.00) = (4+x)(0.60)
solve for "x"
Step-by-step explanation:
Helo
your answer refer to the attachment
When x=-1:

Ok that gives us a little more information.
If we implicitly differentiate with respect to t, from the very start, then we can apply our product rule, ya?

The right side is zero, derivative of a constant is zero.
Where x' is dx/dt and y' is dy/dt.
From here, plug in all the stuff you know:
y' = -3
x = -1
y = 4
and solve for x'.
Hope that helps!
Do you have a picture? Normally this kind of problem features a graph with other points included. -1,6? -6,1? -11,6? -6,11?