

Explanation
(a) First joining XZ and WY, we have < XWY = < XZY = \(\frac{1}{2}\)(180° — 80°) = 50°. This implies that < ZXY = 50°(base angles of an isosceles triangle). So that < XWZ = 180° - 80° = 100°.
(b) The rate in every N1.00 = \(\frac{2}{100}\) so that the rate of interest charged per annum will be \(\frac{2 \times 12}{100}\) x 100 which gives 24%.


