Jo's mother, Anne, is four times as old as Jo. In four years time, Anne will be three times as old as Jo. How old is Jo? (this is an easier version of a riddle we'll do in AP CS)

Jo's age = x = 8 years

Step-by-step explanation:

Let

Jo's age = x

Jo's mother, Anne's age = 4x

In four years time, Anne will be three times as old as Jo.

Jo's age =3( x + 4)

Jo's mother, Anne's age = 4x + 4

How old is Jo?

Equate Jo's age and his mother's age

3(x + 4) = 4x + 4

3x + 12 = 4x + 4

3x - 4x = 4 - 12

-x = - 8

Divide both sides by -1

x = 8

Therefore,

Jo's age = x = 8 years

yes the total will be same because in both of them the expression.is rearranged but their sign remains the same hence it hss just been shuffled

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