Answer:
60miles
Step-by-step explanation:
if they drove x miles in the city and y miles on the highway then you know that
x + y = 280
x/12 + y/20 = 16
x + 12y/20 = 16*12 = 192
8y/20 = 88
y = 220
x = 280-y = 280-220 = 60
Move everything to the left hand side and factor, follow this
A group of preschoolers has 30 boys and 13 girls then the ratio of boys to all children would be 30:43.
What is a ratio?
A ratio in mathematics shows how many times one number contains another. For example, if a bowl of fruit contains eight oranges and six lemons, the orange-to-lemon ratio is eight to six. Similarly, the lemon-to-orange ratio is 6:8, and the orange-to-total fruit ratio is 8:14.
A group of preschoolers has 30 boys and 13 girls.
Total children will be = 30 + 13 = 43
Ratio = number of boys/total children
= 30/43.
Hence, if A group of preschoolers has 30 boys and 13 girls then the ratio of boys to all children would be 30:43.
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Answer
(a)

(b)

Step-by-step explanation:
Remember that when you want to solve a problem like this, you express the equation as following

So, if you know the inverse of
then

For this case

Now for this case the inverse of A would be

Then when you multiply with the vector solution

So from that information you can conclude that the solution to the system of equations is x = 500/7 y = 2400/7 and z = 2700/7
Answer:
(2)
Step-by-step explanation:
Let f(x) = y → f-¹(x) = f(y) = x, f(y) is the inverse of f(x)
Thus,
=> -x³ - 9 = y
=> - y - 9 = x³
=> (-y - 9)^(1/3) = x
=> f(y) = x
Inverse is (-y-9)^(1/3)
Replacing the variable, inverse is (-x-9)^(1/3)
Option (2)