# math

posted by .

Decrease a number by 5, divide the result by 2, then add 17 and multiply by 5. If the final result is 100, with what number did you start?

• math -

[( x-5)/2 + 17] * 5 = 100

Divide both sides by 5.

(x - 5)/2 + 17 = 20

Subtract 17 from both sides.

(x - 5)/2 = 3

Multiply both sides by 2.

x - 5 = 6

x = 11

## Similar Questions

1. ### math for elementry school teacher

Mr. Mathemagician asks you to pick any whole number. Add 10. Multiply the result by 4. Add 200. Divide by 4. Subtract your original number. Mr. Mathemagician says, “You’re final result is 60!” Explain Mr. Mathemagician’s trick?
2. ### hheeelp

Mr. Mathemagician asks you to pick any whole number. Add 10. Multiply the result by 4. Add 200. Divide by 4. Subtract your original number. Mr. Mathemagician says, “You’re final result is 60!” Explain Mr. Mathemagician’s trick?
3. ### math

I am thinking of a number. If I add 4 to it, square the result, divide that result by 20, and subtract 4, the infal result is 1. What is my number
4. ### Math

Increase a number by 21, multiply the result by 3, then subtract 9, and divide by 5. If the final result is 30, what number did you start with?
5. ### Math

If you multiply a number by 3 and then add 40, the result is the same as if you first add 17 and then multiply by 2. What is the result if you subtract 9 from the number and then multiply by 4?
6. ### Algebra

Pick a number. Double it. Multiply the result by 3. Add 24. Divide by 6. Subtract your original number. Is the result always the same?
7. ### Algebra

Jill asks each of her classmates to choose a number, then multiply the number by -3, add 2 to the product, multiply the result by -2, and then subtract 14. Finally, each student is asked to divide the result by 6 and record the answer. …
8. ### Math

Pick what age you would like to be (may be your actual age if you like). Add 10. Multiply the result by 4. Add 200. Divide by 4. Subtract your original number. The final result is 60. Explain how I knew that.
9. ### Math

Repeat the following procedure for the four given numbers. Add 7 . Double the result. Subtract 4 . Divide by 2. Subtract the original selected number. The 1st number is 1 . The result is 5 . The 2nd number is 4 . The result is 5 . …
10. ### math

think of a number. Triple it. Add 100. double the result. Add 100. divide the result by 4. subtract one a half time the original number. What is the result?

More Similar Questions