Question

FAN+MEDAL
arla's doctor recommended her daily caffeine intake stay under 400 milligrams. Today, Karla has already had 320 milligrams of caffeine. Her favorite soda contains 40 milligrams. Which of the following inequalities could be used to solve for x, the number of sodas Karla can still have today?
a)40x < 720
b)40x < 400
c)40x + 320 < 400
d)40x - 320 < 400

Answer 1

C?

Answer 2

@Daniel_Chernioglo can you help me?

Answer 3

@bibby

Answer 4

we want to stay under 400 so 400 has to be on the right side of the inequality
that cancels a

she has 40 for every soda x, (40*x or 40x) added to the 320 she already had

Answer 5

okay njext step

Answer 6

40x added to the 320 =40x+320
we want that whole sum to be under 400

Answer 7

sorry for the late reply... ya i agree with @bibby

Answer 8

so... im pretty sure you are correct, right @bibby

Answer 9

so c because that would equal 360

Answer 10

right?

Answer 11

it wouldn't, it'd equal 40x+320
think of x's as squares and numbers as circles.
you can't add squares and circles or apples and oranges
you can only add squares and squares