50 is 40% of what number?

Plz me plz i will give a brain just plz

Find the gradient of f(x,y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).

The temperature of chicken soup is 192.7°f. as it cools, the temperature of the soup decreases 2.3°f per minute. what is the temperature in degrees fahrenheit of the soup after 25 minutes? a. 27.3°f b. 57.5°f c. 135.2°f d. 250.2°f