Equation Problem

Question

Katie: "Think of a number. Add 6. Multiply by 5. Subtract 28. Double it. Add 16. Multiply by 5. Subtract 50. Double it. Now tell me your result."

 

Jeff: "900."

 

Katie quickly found the original number selected by Jeff. Explain her method and use the equation strategy to show how she found the original number.

 

The equation strategy is just to make an equation. Please help, thanks. 

Answer 1

((((N+6)x5-28)x2+16)x5-50)x2=900

 

This is the equation for the operations described by the text. Solving for N gives the result.

An equation like this can be simplified significantly, which Katie probably would have done in advance. Then she could solve the simpler equation much more quickly than the form shown above.