Please help me answer my math problem as soon as possible

Question

Dee is planning to bring a great deal of 24 exposure for films and oversea safari. A photograph store is selling 6 packs of film for $17.38 and 15 packs of the same film for $39.98.

 

A)If She wishes to purchase only 6 packs and 15 pack and to spend a maximum of $175 what is the maximum numbers of rolls of film she can purchase?

 

B )how much does she spend? 

 

Answer 1

OK, here's a quick response, perhaps not the most mathy way to get answer...

The 6-packs cost 17.38/6 = 2.90 (rounded to two digits) per pack

The 15-pack costs 39.98/15 = 2.67 (" ) per pack.

So we do get more per dollar with the 15 pack - so buying 15 packs is best -

except that it can leave money left over.

Most 15 packs we could get:

  175/39.98 = 4 + ~ $15 left over.  That's a lot left over and not enough for a 6 pack.

What if we got one less 15 pack and used the left over for 6 packs?

  3 * 39.98 = 119.94, leaving 55.06 from the $175,

so with 55.06 we can get 55.06/17.38 = 3 packs with 2.92 left over (not too much)

  For fun go once further check if we buy 2 15 packs:

  2 * 39.98   leaves $95.04 which would get 5 6-packs with some left over

 

So compare:  

   4 x 15-packs = 60 rolls and $15 left.

  vs

     3 x 15 pack = 45 rolls plus 3 x 6 = 18 rolls  = 63 rolls with $2.92 left over.

    2 x 15 packs = 30 rolls  plus 5 x 6 = 30 rolls = 60 rolls with $8.14 left.

 

So 3 15-packs and 3 6-packs is best,

A)  63 rolls,

B) for $172.08