Weeks X months to be done is that order
The proportion is 0.4401.
We find z-scores that correspond with both ends of this interval. Z-scores are given using the formula:

For the lower end,

The proportion of scores to the left of this number is 0.2514.
For the higher end, the z-score is

The proportion of scores to the left of this number is 0.6915.
To find just the proportion of scores between these two, we subtract;
0.6915-0.2514 = 0.4401.
From my understanding you ahould use the trig function cos to solve this.
cos(c) = 15/25 or 0.6
if you have this following function on your calculator I suggest using it:
cos ^{ - 1}
by using the function like so:
cos^{ - 1} (0.6
you should get about 53.13° (rounding to the nearest hundredth)
Hope this helped.
(-4)-4 could be some integers to subtract and get -8
(x + 4)*3 - 4 = 65
3x + 12 - 4 = 65
3x = 65 - 12 + 4
3x = 57 |:3
x = 19 <-- Answer
(19+4)*3-4 = 23*3-4 = 69-4 = 65