Option 1 -> This represents the total amount paid for 3 pounds, not the rate per pound.
Option 2 -> Incorrect calculation of the exchange rate.
Option 3 -> This is the number of pounds, not the exchange rate.
Option 4 -> Dividing Rs 150 by 3 pounds gives Rs 50 per pound.
Hence, Option 4: Rs. 50 -> To find the exchange rate per pound, we divide the total amount by the number of pounds: Rs 150 ÷ 3 pounds = Rs 50 per pound. This means for every 1 pound, we need to pay Rs 50. -> correct