Question

Zoe thinks of a number. She multiplies it by 3 and adds 4. She gets the same answer when she adds 5 to the number and then multiplies the result by 2.

a. Write an equation, using n for Zoe's number.

b. Solve your equation to find Zoe's number.​

Answer 1

21 is probably the best answer

Answer 2

Zoe's number is 6

Explanation:

Let the number be 'n'

a) Multiply 'n' by 3 ⇒ n*3 = 3n

Add 4 to '3n' ⇒ 3n + 4

Add 5 to 'n' ⇒ n +5

Multiply (n+ 5) by 2 ⇒ (n +5)*2 = 2n + 5*2 = 2n + 10

3n + 4 = 2n + 10

b) 3n + 4 = 2n + 10

Subtract 4 form both sides

3n = 2n + 10 - 4

3n = 2n + 6

Subtract 2n from both sides

3n - 2n = 6

`\sf \boxed{\bf n = 6}`