A piece of rope is cut into 3 pieces, A, B and C. The length of rope A is thrice the length of rope B. Rope C is half of rope B. Half of rope A is 12 cm. How much longer is rope A than rope C?
Let's denote the length of rope B as x.
Therefore, the length of rope A would be 3x.
And the length of rope C would be 0.5x.
Given that half of rope A is 12 cm, we can find the length of rope A:
3x/2 = 12
3x = 24
x = 8
So, the length of rope A is 3(8) = 24 cm and the length of rope C is 0.5(8) = 4 cm.
Therefore, rope A is 24 - 4 = 20 cm longer than rope C.