minu purchases a pair of sunglasses at rs 1000 and sells to kanu at 20% profit. then kanu sells it back to minu at 20% loss. finally minu sells the same pair of sunglasses to tanu. if the total profit is made by minu from all the transactions is rs 500, then the percentage of profit made by minu when she sold the pair of sunglasses to tanu is

31.25 percent?

cp of minu =1000
profit of minu =20%
(1+20/100)*1000= 6/5*1000=1200 rupees
kanu sells it back to minu at 20%loss that means 4/5*1200=960
again minu sells sunglasses to tanu where total profit for minu is 500
we know from first transaction profit is 1200-1000=200
so we need excess 300 profit so
x/100*960=300
24x/25=300
therefore x=300*25/24=31.25%
profit percentage made by minu is 31.25%
hope it helps