Question

The frequency with which a cricket chirps varies directly with the temperature. If the cricket chirps 100 times per minute in 80° weather, it will chirp how many times per minute in 92° weather?
A) 87
B) 90
C) 95
D) 115

Answer 1

The answer is: D) 115

The explanation is shown below:

1. You have that the frequency with which a cricket chirps varies directly with the temperature, which you can express it as following:

$y=kx$

Where $y$ is the frequency with which a cricket chirps, $x$ is the temperature and $k$ is the constant of proportionality.

2.  If the cricket chirps 100 times per minute in 80° weather, you can calculate $k$ as below:

$k=\frac{100}{80}=1.25$

3. Therefore, the frequency in 92° weather is:

$y=1.25x\\y=(1.25)(92)\\y=115$