Answer:
6
Explanation:
Let n be the unknown number.
"Twice a number" means to multiply the number by 2:
⇒ 2n
"Increase by 8" means to add 8:
⇒ 2n + 8
"Is 20" means equals 20:
⇒ 2n + 8 = 20
Therefore, the equation is: 2n + 8 = 20
To solve, subtract 8 from both sides:
⇒ 2n + 8 - 8 = 20 - 8
⇒ 2n = 12
Divide both sides by 2:
⇒ 2n ÷ 2 = 12 ÷ 2
⇒ n = 6
Therefore, the unknown number is 6.