At a specialty nut store, almonds cost $4.30 per pound and walnuts are priced at $3.75 per pound. How many pounds of walnuts are in a 12-pound mixture priced at $47.75?
check my answer?

Question

At a specialty nut store, almonds cost $4.30 per pound and walnuts are priced at $3.75 per pound. How many pounds of walnuts are in a 12-pound mixture priced at $47.75?  
check my answer?

anonymous · Answer

answer choices are:
4
5
6
7

I got 5

amistre64 · Answer

lets see if that fits

amistre64 · Answer

5lbs + 7lbs = 12lbs

3.75(5) + 4.30(7) =? 47.75 ;  no

anonymous · Answer

The correct answer is 7.

anonymous · Answer

thank you, @escrite, but i would like to know HOW to get that answer

amistre64 · Answer

3.75(5) + 4.30(7)  is a close guess, that we can adjust if need be

3.75(5) + 4.30(7) = 48.85  ... its too heavy

3.75(6) + 4.30(6) = 48.30  ... its too heavy

3.75(7) + 4.30(5) = 47.75   just right


i think you did it correctly but got the a and ws mixed up

anonymous · Answer

oooohhhhh.... yup, that was my mistake. thanks!

amistre64 · Answer

substitution for this is simple enough

 w +  a = 12      :  a = 12-w

3.75w + 4.30a = 47.75

3.75w + 4.30(12-w) = 47.75

solve for w