Mock Set 1 Paper 02 Calculator

\begin{aligned} &\text{Initial ratio: } 5:3:4, \; \text{Ben's share } = 3k = ninety \\ &k = 30. \\ &\text{Alex: } 5k = 150, \quad \text{Ben: } 90, \quad \text{Carl: } 4k = 120. \\ &\text{Final ratio: } 4:5:3, \text{ let multiplier be } m. \\ &\text{Alex: } 4m, \quad \text{Ben: } 5m, \quad \text{Carl: } 3m. \\ &\text{Total initially: } 150 + 90 + 120 = 360, \quad \text{total finally: } 12m. \\ &12m = 360 \Rightarrow m = 30. \\ &\text{Final shares: Alex: } 120, \; \text{Ben: } 150, \; \text{Carl: } 90. \\ &\text{Carl had initially 120, now 90, so he gave away 30. Of this, Alex's loss is } 150 - 120 = 30, \; \text{so all of Carl's loss went to Alex. Wait, wrong — checking…} \\ &\text{Actually, Ben had 90, now 150, so gained 60. Alex had 150, now 120, so lost 30. The remaining 30 gained by Ben came from Carl.} \\ &\text{Carl gave to Ben: } £18 \end{aligned}