A crown made of gold and copper weighs 210g in air and 198 g in water. the weight of gold in crown is

Question

A crown made of gold and copper weights 210 g in air and 198 g in water. The weight of gold in crown is-

[given : density of gold = 19.3 gm/cm3 and density of copper = 8.5gm/cm3]

(A) 93 g

(B) 100 g

(C) 150 g

(D) 193 g

Answer 1

The correct option is (D) 193 g.

Explanation:

Loss of weight in water = Weight in air − Weight in water

= 210−198

= 12 grams

Volume of the crown in cm3= Loss of weight in grams =12 cm3

Expression for RD:

RD = Weight in air/Loss of weight

Let,

mass of gold = x

Hence,

Loss of weight of gold + Loss of weight of copper = 12 grams

x/19.3 + 210−x/8.5 =12

8.5 x − 19.3 x + 4053 = 1968.6

10.8 x = 2084.4

x = 193 grams