David gave 1/5 of his oranges to his brother. his brother got 15 oranges. he gave his friend donny 1/3 of the remainder.
1 answer:
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Answer:
- movie: $3.75
- video game: $5.75
Step-by-step explanation:
Two equations in two unknowns can be written:
3m +5v = 40
9m +7v = 74
These can be solved a variety of ways. One of them is using Cramer's rule. It tells you the solution to
- ax +by = c
- dx +ey = f
is given by ...
- ∆ = bd -ea
- x = (bf -ec)/∆
- y = (cd -fa)/∆
For the numbers above,
- ∆ = 5·9 -7·3 = 24
- m = (5·74 -7·40)/24 = 90/24 = 3.75
- v = (40·9 -74·3)/24 = 138/24 = 5.75
The rental cost for each movie is $3.75; for each video game, it is $5.75.
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The attached graph shows a graphing calculator solution to these equations.
