Thursday

April 24, 2014

April 24, 2014

Posted by **Sandra** on Wednesday, October 17, 2012 at 12:02am.

- math -
**Anonymous**, Wednesday, October 17, 2012 at 12:35amLet x = 15$ paint

- math -
**Reiny**, Wednesday, October 17, 2012 at 9:17amNumber of $15 cans --- x

number of $20 cans --- y

15x + 20y = 320

divide by 5

**3x + 4y = 64**

we are looking at the equation of a straight line, where the solutions can only be integers, (can't buy a partial can of paint)

x-intercept = 64/3 , x < 21

y-intercept = 64/4 , y < 16

3x = 64-4y

x = (64-4y)/3

64-4y must be a multiple of 3

with y as an integer, 64-4y can only be

60 56 52 48 44 40 36 32 28 24 20 16 12 8 4

of those the only multiples of 3 are:

60 48 36 24 and 12

so, assuming they buy at least one of each can, possible solutions for (x,y) are

(20,1)

(16,4)

(12,7) ---- your answer

(8,10)

(4,13)

**Related Questions**

Math - How many gallons of paint are necessary to paint the walls of a 15' by 12...

Math - My original question: How many gallons of paint are necessary to paint ...

PRE-ALGEBRA - Paint costs $21 per gallon is to be mixed with 6 gallons of paint ...

math question grade 8!! - shelby wants to paint the walls and ceiling of a ...

math - You brought home 1/2 of a can of paint. You then used 2/3 of the paint to...

math - A can of paint and a paint brush cost a total of $35. If the can of paint...

math - peter needs 1/2 gallon of white paint,2 gallons of magenta paint, and 1 ...

Math - The jars of paint in the art room are full of different amounts of paint....

Math - 1 litre can of paint covers 11m squared. How many cans of paint would you...

Physics - A partly-full paint can has 0.83 U.S. gallons of paint left in it. (a...