Given:
new game cost - $ 64
used game cost - $ 43
Luis spent $ 343
Required:
Number of used games Luis purchased
Solution
Let: x be the number of new games Luis bought
x + 3 be the number of used games Luis bought
Total cost = $ 343
Total Cost = (No. of new games bought)(Cost of new games) + (No. of used games bought)(Cost of used games)
$ 343 = ( x ) ( $ 64 ) + ( x + 3 ) ( $ 43 )
343 = 64x + 43 ( x + 3 )
343 = 64x + 43x + 129
343 - 129 = 107x
214 = 107x
2 = x
x = 2
x be the number of new games Luis bought 2
x + 3 be the number of used games Luis bought 2 + 3 = 5
Answer:
Luis purchased 5 used games
To check:
Substitute x into the equation,
343 = x ( 64 ) + (x + 3 ) (43)
343 = 2 ( 64 ) + (2 + 3)(43)
343 = 2 (64) + (5) (43)
343 = 128 + 215
343 = 343
The computed value of x satisfies the equation, Our answer is correct.