Question

The total weight of 3 rocks is 7 kg 700 g. The weight of the first two rocks are given in the table.


The weight of the third rock is .

• A. 1 kg 925 g
• B. 2 kg 925 g
• C. 1 kg 935 g
• D. 2 kg 935 g

Answer 1

The correct option is A 1 kg 925 g

Weight of Rock 1 = 1 kg 450 g
Weight of Rock 2 = 4 kg 325 g

Total weight of the three rocks = 7 kg 700 g

∴ Weight of Rock 3 can be written as:


To calculate the weights of Rock 1 and Rock 2, we calculate the sum of 1 kg 450 g and 4 kg 325 g.

Converting the weights from kilograms to grams, we get:


So, (1 kg 450 g + 4 kg 325 g) can be calculated as (1450 g + 4325 g).

Calculating 1450 + 4325 using the standard method, we get:


∴ The total weight of Rock 1 and Rock 2 is 5775 g.

Hence, we can see:


Calculating 7700 - 5775 using the standard method, we get:


∴ The weight of Rock 3 = 1925 g
= 1 kg 925 g