Question

This expression, 1.8C + 32, shows how to convert from degrees Celsius to degrees Fahrenheit, where C represents the temperature in degrees Celsius. What is the temperature in degrees Fahrenheit when the temperature is 25°C?

Answer 1

`77^@F`

Explanation:

If you notice that `1.8=18/10`
then this can be done (or almost done) in your head:

`18/10*25+32`

`color(white)("XXX")=18/2*5+32`

`color(white)("XXX")=9*5+32`

`color(white)("XXX")=45+32`

`color(white)("XXX")=77`