Fatima wants to mail three parcels to three village schools. She finds that the postal charges are Rs 20, Rs 28 and Rs 36, respectively. If she wants to buy stamps only of one denomination, what is the greatest denomination of stamps she must buy to mail the three parcels?
Since, Fatima wants to buy stamp of only one denomination
It should be a factor of 20, 28, 36
Largest such number = HCF of 20, 28, 36 = 4
Hence, the greatest denomination of stamps she must buy to mail the three parcels = Rs. 4