Container A and Container B collected \( 77 \ell \) of rainwater in total. Mr Zul drained off \( 14 \ell \) of the rainwater from Container A and \( \frac{3}{8} \) of the rainwater from Container B. The volume of rainwater in Container A was \( \frac{1}{2} \) of the volume of rainwater in Container B in the end. How much rainwater did Mr Zul drain off altogether?

Let's denote the amount of rainwater originally in Container A as \( a \) and in Container B as \( b \). According to the information given: 1. \( a + b = 77 \) 2. After draining, the amount in Container A is \( a - 14 \) and in Container B is \( b - \frac{3}{8}b = \frac{5}{8}b \). 3. At this point, we have the equation: \[ a - 14 = \frac{1}{2} \left(\frac{5}{8}b\right) \] Now, we can solve these equations step by step: First, simplify the third equation: \[ a - 14 = \frac{5}{16}b \] Now substitute \( b = 77 - a \) into this equation: \[ a - 14 = \frac{5}{16}(77 - a) \] Multiply both sides by 16 to eliminate the fraction: \[ 16(a - 14) = 5(77 - a) \] \[ 16a - 224 = 385 - 5a \] Now, move \( 5a \) to the left side: \[ 16a + 5a = 385 + 224 \] \[ 21a = 609 \] Now, divide by 21: \[ a = 29 \] Now substitute \( a \) back to find \( b \): \[ b = 77 - a = 77 - 29 = 48 \] Now, we can find out how much rainwater he drained off: - From Container A, he drained \( 14 \ell \). - From Container B, he drained \( \frac{3}{8} \cdot 48 = 18 \ell \). Thus, the total rainwater Mr. Zul drained off is: \[ 14 + 18 = 32 \ell \] So altogether, Mr Zul drained off \( 32 \ell \) of rainwater.