Question

Tiffany pays \[\$ 40\;{\text{for}}\;160\] minutes of talk time on her cell phone. How many minutes of talk time does she get per dollar?

Answer 1

Hint:Assume the required minutes of talk time to be a variable (say “x”), then find the ratio of given dollars to the given talk time and equate it with the respective ratio of one dollar to “x” minutes, from that equation find the value of “x”, and hence find the required talk time.

Complete step by step solution:
In order to find how many minutes of talk time Tiffany gets per dollar if she is paying \[\$ 40\;{\text{for}}\;160\] minutes of talk time, we will first assume the required minutes of talk to be $x$ minutes and then equate the ratio of given dollars to the given minutes of talk time and the respective ratio of one dollar to $x$ minutes. So let us find both ratios first,
Ratio of given dollars and minutes of talk time is given as: $\dfrac{{40}}{{160}} = \dfrac{1}{4}$
Ratio of one dollar to $x$ minutes of talk time: $\dfrac{1}{x}$
Now equating both the ratios, to get the value of $x$
$
\Rightarrow \dfrac{1}{4} = \dfrac{1}{x} \\
\Rightarrow x = 4 \\
$
Therefore, Tiffany is getting four minutes of talk time for her each dollar.

Note: We have equated both the ratios, because the ratio is showing the rate of dollars per minutes and cannot be changed for any pair of dollars (or money) and time of talk time of that particular network company whose consumer Tiffany is. Sometimes in this type of questions, there are different units present for a particular physical quantity, so first convert them all into similar units then precede.