It takes Zina 1 hours to build a model skyscraper and Rachel 3 hours to do the same job. It will take hours to build a model skyscraper working
together?

It takes them 45 minutes

Step-by-step explanation:

Let's say that x is the amount of work in one hour that zina does

so the amount of work that rachel does in the same hour is 1/3x, because 3 times slower

so we have

x+1/3x=100%

what does that mean?

it means the amount of hours taken to complete a skycraper

so we solve for x

x=75%

so we need to figure out how much hours does zina takes to complete 75% of the skycraper

1 hour 100%

x hours 75%

1 hour *75%/100%=x hours

1 hour (3/4)=x hours

60 minutes (3/4)= x minutes

x=45 minutes

.95

step-by-step explanation:

simplifying

5(x + -6) = 2(x + 3)

reorder the terms:

5(-6 + x) = 2(x + 3)

(-6 * 5 + x * 5) = 2(x + 3)

(-30 + 5x) = 2(x + 3)

reorder the terms:

-30 + 5x = 2(3 + x)

-30 + 5x = (3 * 2 + x * 2)

-30 + 5x = (6 + 2x)

solving

-30 + 5x = 6 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-30 + 5x + -2x = 6 + 2x + -2x

combine like terms: 5x + -2x = 3x

-30 + 3x = 6 + 2x + -2x

combine like terms: 2x + -2x = 0

-30 + 3x = 6 + 0

-30 + 3x = 6

add '30' to each side of the equation.

-30 + 30 + 3x = 6 + 30

combine like terms: -30 + 30 = 0

0 + 3x = 6 + 30

3x = 6 + 30

combine like terms: 6 + 30 = 36

3x = 36

divide each side by '3'.

x = 12

simplifying

x = 12

this should .