-6 + x = -7
+6 +6 add 6 to both sides, 6's cancel out on the left.
________
x = -1, is the answer.
Hope this helps! Let me know if you have any other questions related to this problem. :)
Answer:
450 ounces
Step-by-step explanation:
We know that the cost of the mixture
must be the cost of the everyday moisturizing lotion
plus the cost of the self-tanning lotion
, which means
.
The cost of any substance will be the cost per ounce of the substance (c), multiplied by the number of ounces (n), which means C=nc, so we have from the previous formula that we have:
![n_m c_m=n_e c_e + n_s c_s](https://tex.z-dn.net/?f=n_m%20c_m%3Dn_e%20c_e%20%2B%20n_s%20c_s)
But we also know that the number of ounces of the mixture must be the sum of the number of ounces of the everyday moisturizing lotion with the number of ounces of the self-tanning lotion, so we have
![n_e c_e + n_s c_s=n_m c_m=(n_e+n_s) c_m=n_e c_m+n_s c_m](https://tex.z-dn.net/?f=n_e%20c_e%20%2B%20n_s%20c_s%3Dn_m%20c_m%3D%28n_e%2Bn_s%29%20c_m%3Dn_e%20c_m%2Bn_s%20c_m)
We want to calculate the number of ounces of the self-tanning lotion (
), so we solve for that variable:
![n_e c_e + n_s c_s=n_e c_m+n_s c_m](https://tex.z-dn.net/?f=n_e%20c_e%20%2B%20n_s%20c_s%3Dn_e%20c_m%2Bn_s%20c_m)
![n_s c_s-n_s c_m=n_e c_m-n_e c_e](https://tex.z-dn.net/?f=n_s%20c_s-n_s%20c_m%3Dn_e%20c_m-n_e%20c_e)
![n_s (c_s-c_m)=n_e(c_m-c_e)](https://tex.z-dn.net/?f=n_s%20%28c_s-c_m%29%3Dn_e%28c_m-c_e%29)
![n_s=\frac{n_e (c_m-c_e)}{(c_s-c_m)}](https://tex.z-dn.net/?f=n_s%3D%5Cfrac%7Bn_e%20%28c_m-c_e%29%7D%7B%28c_s-c_m%29%7D%20)
And substitute our values in this formula, to get:
![n_s=\frac{(700\ ounces) (\$1.6-\$0.7)}{(\$3-\$1.6)}=450\ ounces](https://tex.z-dn.net/?f=n_s%3D%5Cfrac%7B%28700%5C%20ounces%29%20%28%5C%241.6-%5C%240.7%29%7D%7B%28%5C%243-%5C%241.6%29%7D%3D450%5C%20ounces%20)
Answer:
Step-by-step explanation:
small=s, s=3.99
large=l, l=19.20
10s+8l=192.20
20s+l=99
we can see that in the second equation, 20s+l=99
l=99-20s
lets replace l in the first equation
10s+8(99-20s)=192.20
10s+792-160s=192.20
-150s=-792+192.20
150s=599.80
s=3.99
l=99-20(3.99)=99-79.80=19.20