Answer
0.1613.
Work Step by Step
$z_1=\frac{value-mean}{standard \ deviation}=\frac{120-100}{15}=1.333.$ $z_2=\frac{value-mean}{standard \ deviation}=\frac{110-100}{15}=0.667.$ Using the table, the value belonging to 1.333: 0.9099, the value belonging to 0.667: 0.7486. Hence: 0.9099-0.7486=0.1613.