Question

• How many coins are there in a sack of 5 rupee coins if it weighs:
(a) 18 kg? ________
(b) 54 kg? ________
(c) 4500 g? ________
(d) 2 kg and 250 g? ________
(e) 1 kg and 125 g? ________
• A 2 rupee coin weighs 6 g. What is the weight of a sack with:
(a) 2200 coins? ______ kg ______ g
(b) 3000 coins? ______ kg
• If 100 one rupee coins weigh 485 g then how much will 10000 coins weigh? ____ kg ____ g

Answer 1

1 kg = 1000 g
Weight of a 5 rupee coin = 9 g

(a) Weight of 18 kg sack in grams = 18 $\times$ 1000 = 18000 g
Number of 5 rupee coins in 18 kg sack = 18000 ÷ 9
= 2000

(b) Weight of 54 kg of sack in grams = 54 $\times$ 1000 = 54000 g
Number of 5 rupee coins in 54 kg sack = 54000 ÷ 9
= 6000

(c) Weight of sack = 4500 g
Number of 5 rupee coins in 4500 g sack = 4500 ÷ 9
= 500

(d) Weight of 2 kg 250 g sack = 2 $\times$ 1000 g + 250 g
= 2000 g + 250 g
= 2250 g
Number of 5 rupee coins in 2250 g sack = 2250 ÷ 9
= 250

(e) Weight of 1 kg 125 g sack = 1 $\times$ 1000 g + 125 g
= 1000 g + 125 g
= 1125 g

Number of 5 rupee coins in 1125 g sack = 1125 ÷ 9
= 125


• We know,
1 kg = 1000 g
Weight of a 2 rupee coin = 6 g

(a) Now, weight of sack with 2200 coins = 2200 $\times$ 6 = 13200 g
= 13 $\times$ 1000 g + 200 g
= 13 kg 200 g


(b) Weight of the sack with 3000 coins = 3000 $\times$ 6 = 18000 g
Thus, 18000 g = 18 $\times$ 1000 g
= 18 kg

• Weight of 100 one-rupee coins = 485 g
So, weight of a single one-rupee coin = $\frac{485}{100}$ = 4.85 g
Thus, weight of 10000 one-rupee coins = 10000 $\times$ 4.85
= 48500 g

So, 48500 g = 48 $\times$ 1000 g + 500 g
= 48 kg 500 g