Maximum density of $H_2O$ is at the temperature

$A$ Centigrade and a Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers $140\,^{\circ}F$. What is the fall in temperature as registered by the centigrade thermometer?

On a temperature scale $Y$, water freezes at $-160^{\circ} Y$ and boils at $-50^{\circ} Y$. On this $Y$ scale, a temperature of $340 \ K$ is (in $^{\circ} Y$)

Calculate the temperature which has the same numerical value on the Celsius and Fahrenheit scales.

The pressure of a gas filled in the bulb of a constant volume gas thermometer at temperatures $0^{\circ} C$ and $100^{\circ} C$ are $27.50 \, cm$ and $37.50 \, cm$ of $Hg$ respectively. At an unknown temperature,the pressure is $32.45 \, cm$ of $Hg$. The unknown temperature is ........ $^{\circ} C$.

What is the difference between $^oC$ and $^oF$ thermometer values for freezing and boiling points of water?