The greatest capacity of such a bag should be 10 kg.
To find the greatest capacity of a bag that can measure out all three quantities of rice exactly, you need to find the Highest Common Factor (HCF) or Greatest Common Divisor (GCD) of 120, 160, and 210.
Find the prime factors of each number:
120=2×2×2×3×5=23×3×5
160=2×2×2×2×2×5=25×5
210=2×3×5×7
Identify the common factors:
Multiply the lowest powers of the common factors:
Therefore, the maximum capacity of each bag must be 10 kg.