List the three properties of a thermometer​

PropertyThermometer

Volume expansion of a gasGas thermometer

Volume expansion of a liquidLaboratory or clinical thermometer

Volume expansion of a solidBi-metallic strip thermometer

Pressure change of a fixed mass of gasConstant – volume gas thermometer

Changes in e.m.f.Thermocouple

Changes in electrical resistanceResistance thermometer or thermistor

Changes in wavelength Pyrometer

Changes in magnetic flux or sound energy Magnetic or sonic thermometer

Volume expansion of a gas- Gas thermometer

Volume expansion of a liquid- Laboratory or clinical thermometer

Volume expansion of a solid- Bi-metallic strip thermometer

Pressure change of a fixed mass of gas- Constant – volume gas thermometer

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form