SSC MTS 2 Aug 2019 Shift 2 Paper

Average weight = Total weight/Number of coins
⇒ The average weight of 8 gold coins = 20 g
⇒ Total weight of 8 coins = 160 g
⇒ The average weight of 12 silver coins = 35 g
⇒ Total weight of 12 silver coins = 420 g
⇒ The average weight for 20 coins = (160 + 420)/(8 + 12)
⇒ The average weight for 20 coins = 580/20 = 29 g
∴ The average weight is 29 g per coin for 20 coins.