alfretztay Post on Sat, 14/10/2017 1:11pm Before — Jane : 8u May : 1u After — Jane : 8u – 25 ——- 3p May : 1u + 25 ——- 1p 8u – 25 ——- (1u + 25) x 3 = 3u + 75 1u ——- (75 + 25)/(8 – 3) = 20 9u ——- 180 Ans : 180 stamps.