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?

Answer 1

[( 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

Add 5 to both sides.

x = 11