Eighteen years ago ivan was three times as old as his son but he is only twice as old now. how old is ivan?

(not a trick question.)

72

Step-by-step explanation:

Let Ivan's current age be g and his son's current age by s.

Then g - 18 = 3(s - 18), and

         g = 2s

Substituting 2s for g in the first equation, we get:

2s - 18 = 3s - 54

Grouping like terms, we get:

36 = s.

Thus, Ivan's son's age now is 36 years; Ivan is twice that, or 72 years.

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".

the 4th choice is the correct one

step-by-step explanation: