Jack bought ten CDs. A week later half of all his CDs were destroyed in a fire. There are only 22 CDs left. How many did he start with?

Answer 1

Let x = # of CDs he started with

x + 10 (total amount of CDs before the fire)

The fire destroys half of the total amount, so divide by 2:

(x + 10)/2 = # of CD's destroyed

x-(x+10)/2 =# of CD's left=22

x/2-5=22

x/2=22+5=27

x=54 which is the # or CD's he started with.

Jim

Answer 2

Let x = # of CDs he started with

x + 10 (total amount of CDs before the fire)

The fire destroys half of the total amount, so divide by 2:

(x + 10)/2 = 22

After the fire he has 22 CDs left.

Now solve.

Multiply each side by 2:

=> x + 10 = 44

Subtract 10 from each side:

=> x = 34

He originally started with 34 CDs.