Troy and Lisa were shopping for school supplies. Each purchased different quantities of the same notebook and thumb drive. Troy bought 4 notebooks and 11 thumb drives for $233. Lisa bought 12 notebooks and 15 thumb drives for $357. Find the cost of each notebook and each thumb drive.

notebook: $6 thumb drive: $19

Step-by-step explanation:

Let n and t represent the cost of a notebook and thumb drive, respectively. Then the two purchases can be represented by the equations ...

4n + 11t = 233

12n + 15t = 357

Subtracting the second equation from 3 times the first gives ...

3 (4n + 11t) - (12n + 15t) = 3 (233) - (357)

18t = 342

t = 342/18 = 19

Putting this into the first equation gives ...

4n + 11 (19) = 233

4n = 24

n = 6

The cost of each notebook was $6. Each thumb drive cost $19.