Interest to be repaid to Ankit at the end of the year =0.08X Interest that Gopal would receive from Ishan in two cases are as given. Case I: if he lends X+Y Interest received =(X+Y)×0.1=0.1X+0.1Y Interest retained by Gopal after paying to Ankit =(0.1X+0.1Y)−(0.08X)=0.02X+0.1Y Given that Interest retained by Gopal is same as that accrued by Ankit ⇒(0.02X+0.1Y)=0.08X ⇒Y=0.6X Case II: if he lends X+2Y Interest received =(X+2Y)×0.1=0.1X+0.2Y Interest retained by Gopal after paying to Ankit
=(0.1X+0.2Y)−(0.08X)=0.02X+0.2Y
Given that interest retained by Gopal would increase by 150
⇒(0.02X+0.2Y)−(0.02X+0.1Y)=150
0.1Y=150 ⇒Y=1500 and X=1500×0.6=2500 Hence X+Y=2500+1500=4000