Question

If 5 pounds of apples cost $3.98 how much will 18 pounds

Answer 1

$14.83
Because you have to divide 3.98 by 5 and then multiply that by 18 and you would then round to get $14.83

Answer 2

We can find the original value of the apple by dividing 5 by 3.98. Now we know that one pound of apple costs $0.80. WAIT. That's not it!!! 
Now we can multiply that value by 18 to get the cost, which is $14.40. Pretty cheap, if you ask me.