Every

Every year the Nguyen's host a family picnic. They know that the cost for each person, s, varies inversely as n, the total number of people who attend the picnic. When 20 people attend the picnic, the cost for each person in $50. How much would the cost be per person if 15 people attend the picnic instead?

$66.7

Step-by-step explanation:

The equation for inverse proportion is calculated as xy=k.

When 20 people attend the picnic, the cost for each person was $50, then k will be= 20 × 50 = 1000

Recall that k = xy

For the second aspect of the question, x= 15, k= 1000.

k= xy

y = k/x

= 1000/15

= 66.7

If 15 people attend the picnic instead, the cost per person will be $66.7

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1