Damasko asked Sophia to choose a number between 1 and 20. He told her to add 7 to that number, multiply by 4, subtract 6 and divide by 2. Sophia's final number was 35. What was her original number? a. 30 c. 12 b. 15 d. 3

12

Step-by-step explanation:

Let n = number

Add 7

n+7

Multiply by 4

4 (n+7)

Subtract 6

4 (n+7) - 6

Then divide by 2

(4 (n+7) - 6) / 2

This is equal to 35

(4 (n+7) - 6) / 2 = 35

Multiply each side by 2

(4 (n+7) - 6) / 2 * 2=35*2

(4 (n+7) - 6) = 70

Add 6 to each side

4 (n+7) - 6+6 = 70+6

4 (n+7) = 76

Divide each side by 4

4 (n+7) / 4 = 76/4

n+7 = 19

Subtract 7 from each side

n+7-7 = 19-7

n = 12