A tank drains at 9.7 litres per hour for 4.2 hours. Estimate using 10 litres per hour and 4 hours. Enter the estimated number of litres.
الإجابة الصحيحة
40
الشرح
The stated benchmarks give 10 × 4 = 40 litres. Adding them to get 14 would mix a rate with a duration and therefore use the wrong operation.