we know that 95 ≤ w ≤ 185 (i am using w instead of T, to match the book).

what we want is something that looks like:

|w - j| ≤ k, which is the same as:

-k ≤ w - j ≤ k

if we add j to everything, we get:

-k + j ≤ w ≤ k + j, which is what we have:

k + j = 185

-k + j = 95

let's add the two equations, to get:

k + j + -k + j = 185 + 95

2j = 280

j = 140 (see where the 140 comes in?)

now we can find k:

k + j = 185

k + 140 = 185

k = 45

as a check, we verify the other equation as well:

-k + j = 95

-k + 140 = 95

-k = -45

k = 45.

now we know that:

95 ≤ w ≤ 185 is the same condition as:

-45 + 140 ≤ w ≤ 45 + 140

-45 ≤ w - 140 ≤ 45

|w - 140| ≤ 45.

it should be obvious what jk is now.