A water heater is guaranteed to heat water to within 125 degrees F of the selected temperature.

Question

Mr.Jones sets his water heater to 130 F. what is the coolest temperature the water could be?

A) 128.75
B ) 129.75

c) 130.25

D) 131.25

im not sure how to answer or break down the question @_@

Answer 1

With a variation of 1.25 ºF guaranteed, the water may actually be between (130 + 1.25) ºF and (130 - 1.25) ºF.  Of course, "the coolest" is 128.75 ºF  (from 130 - 1.25).

 

To do this subtraction, the number 130 is written as 130.00:

               130.00

            -     1.25

             -----------

               128.75