Question

If 2 pounds cost $8.40, whats the cost of 3.5 pounds?
a. $12.50
b.$10.75
c. $14.25
d. $14.70

Answer 1

\(\begin{array}{ccllll}
lbs&\$
\\\hline\\
2&8.40\\
3.5&x
\end{array}\implies \cfrac{2}{3.5}=\cfrac{8.40}{x}\impliedby \textit{solve for "x"}\)

Answer 2

I don't really understand

Answer 3

hint: cross-multiply

Answer 4

hint #2:

Answer 5

notice how I multiplied along the black arrows?

Answer 6

that's what cross multiplying is.

that gives us

2x = 3.5*8.40

solve for x