Mario start collecting stamps in January and buys 12 stamps each month. Karen starts collecting stamps in July and buys 18 starts each month. how many months after Karen starts collecting stamps will she have the same number of stamps as Mario?

12 months

Step-by-step explanation:

Given that:

Mario:

12 stamps per month

Since January

Karen :

18 stamps per month

Starts on july

Number of stamps collected by Mario till the end of June :

12 * 6 = 72 stamps

For Mario :

72 + 12x

For karen:

18x

Where x is the number of months after karen starts :

Equate both equations

72 + 12x = 18x

72 = 18x - 12x

72 = 6x

x = 72/6

x = 12

After 12 months

Number of months after karen starts, will they have same amount of stamp

c. 1,233 miles