Question 1159175
If the center 75.8% of the curve is drawn, that leaves 24.2% divided up on each side, so the z-value giving 0.1210 and the z-value giving 0.8790 will be both equal and the boundaries of the distribution.
z=-1.17 for the first and +1.17 for the second.

z=(x-mean)/sd
1.17=(x-10)/5, since the 25 is the variance, sigma^2
5.85=x-10
x=15.85 upper limit
x=4.15 lower limit