A carton of golf balls weighs 42 lb 4 oz. Of this, 2 lb 11 oz is due to packaging. Find the weight of the golf balls in 7 cartons?

I've set up a conversion equation:
You can just say it out loud what you're trying to do and that will help you write out your ratios.
45.9 grams per 1 ball
1 ounce per 28.35 grams
We have 12 balls
45.9
g
b
a
l
l
⋅
1
o
z
28.35
g
⋅
12
(
b
a
l
l
)
45.9
g
b
a
l
l
⋅
1
o
z
28.35
g
⋅
12
(
b
a
l
l
)
=
45.9
⋅
12
28.35
≈
19.4
o
z