The number of days, d, to build a house is given by 780
d =
W
where w is the number of workers used each day on site.
Bob's company will take 60 days to build the house.
Pat's company will take 39 days to build the house.
Pat's company will have to use more workers each day than Bob's company.
How many more?

Step-by-step explanation: 7 more workers

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places