Savanna is playing a game with her friends. She tells them to each pick a number, and then she directs them to: Multiply their number by 5. Subtract 8 from that number. Divide that number by 2.

Question

Zach says his "new" number is n. What number did Zach start with?

Answer 1

So you would work backwards and do the opposite of each step. The last thing he did was divide by 2 so we will multiply by 2 so we have 2n.

Then we have to add because he subtracted 8. So now we have 2n+8.

Finally we have to divide because he multiplied. So it would be (2n+8)/5.

To check, we can work it back. (2n+8)/5 times 5 is 2n+8. 2n+8 minus 8 is 2n. Then 2n divided by 2 would leave you with n.

Therefore we know our answer (2n+8)/5 is correct.

Answer 2

I agree with the person above. Looks well done.

I hope it helps you.