2. Lily pours 296 litres of water into the top of the pipework shown in the diagram. Each time a pipe forks, half the water flows to one side and half to the other. How many litres of water will reach container $\mathrm{Y}$ ?
A 210
B 213
C 222
D 225
E 231
Solution
C

Consider first the amount of water that will reach $X$. Since half the water flows to each side each time a pipe forks, the amount of water, in litres, reaching $X$ is $\frac{1}{2} \times \frac{1}{2} \times 296=74$. Therefore the amount of water, in litres, reaching $Y$ is $296-74=222$.