Well, first you have to do some calculations.

You will start with finding Z at the lower limit which will be z(LL) = (10 - 15.1)/4.3. The result is -1.19. You will find this value in the z table. This will be equivalent to 1 - .8830. Then you will find the Z at the upper limit. This will be equal to (26-15.1)/4.3. This will be equivalent in the curve to .9943.

Now that you have this two points in the curve, you would subtract .1170 from .9943. The probability then will be .8773