4 minutes → 4 x 60 seconds = 240 seconds
128 notebooks → 240 seconds 1 notebook → 240 ÷ 128
16 notebooks → 240 ÷ 128 x 16 = 30 seconds
A machine produces 128 notebooks in 4 minutes. At this rate, how long does the machine take to produce 16 notebooks? Give your answer in seconds. (2 marks)
Answer: 30 s
4 minutes → 4 x 60 seconds = 240 seconds
128 notebooks → 240 seconds 1 notebook → 240 ÷ 128
16 notebooks → 240 ÷ 128 x 16 = 30 seconds