Marta was pregnant 268 days, 258 days, and 271 days for her first three pregnancies. in order for marta’s average pregnancy to equal the worldwide average of 266 days, for how long must her fourth pregnacy last? for marta's average pregnancy to equal the worldwide average of 266 days, for how long must her fourth pregnancy last?

To find the average, you add all of the numbers and divide by the number of numbers (If that makes sense)

We can use variables (x) to solve for the last number.

268+258+271+x/4 = 266

Multiply both sides by 4

268+258+271+x = 266*4

268+258+271+x = 1064

Add the three numbers together

797+x = 1064

Subtract both sides by 797

x = 267

Her fourth pregnancy must last 267 days.

267

Step-by-step explanation:

So we want to find the average of 4 numbers:

268, 258, 271, and x

The average of those 4 numbers is represented by the fraction:

Now we also wanting this average to be equal to 266.  We need to find x such that that happens.

So we have the following equation to solve:

Multiply both sides by 4:

Do any simplifying on both sides:

Subtract 797 on both sides:

Simplify:

{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

35 is an outlier

step-by-step explanation: