A first number plus twice a second number is 4. Twice the first number plus the second totals 17. Find the numbers

10; -3

Step-by-step explanation:

Let's represent the first number with x, and the second number with y.  Now let's write these two equations to find the numbers.

x + 2y = 4

2x + y = 17

We can solve using the substitution method:

x = 4 - 2y

2x + y = 17

2 (4 - 2y) + y = 17

8 - 4y + y = 17

-3y = 9

y = -3

Now plug the value of y in to find x:

x + 2y = 4

x + 2(-3) = 4

x + -6 = 4

x = 10

So, the first number is 10, and the second number is -3.

Cheers.

22 and 22

step-by-step explanation:

10 plus 12 equals 22.

12 plus 10 also equals 22 because regardless of what order they're in, they're gonna equal the same thing.

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

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