Word problem in ten description

Question

Paige bought 10 packs of bubblegum. A pack of trident costs $1.80,and a pack of orbit costs $2.40. If Paige spent a total of $21.60 on a pack of bubblegum, how many packs of each type did she buy? (Excluding tax!)

 

 

have to to slove with system of equation

Answer 1

Let d = trident and b = orbit

Here's what we know:

d + b = 10 (ten packs purchased)

1.8d + 2.40b = 21.60 (total of gum is $21.60)

 

You can solve this either by substitution (isolating a variable in the first equation) or elimination (multiplying the first equation by -1.8)

 

I'm actually tempted to do elimination in this case, so that's what I'll do:

-1.8(d + b = 10)

becomes:

-1.8d - 1.8b = -18

1.8d + 2.4b = 21.60

-------------------------

.6b = 3.6

 

Divide both sides by .6:

b = 6

 

d + 6 = 10

d = 4

 

Check:

1.8 * 4 + 2.4 * 6 = 21.60

7.2 + 14.4 = 21.6

21.6 = 21.6