Page 59 - Whole Numbers (Addition and Subtraction)

Mr Naidoo has three 10 000-litre water tanks in his vegetable
garden. While watering his plants one day, he measures the water
levels in the tanks each hour. His readings in litres are shown in
the tables below.

Tank A

Time of the day 10:00 11:00 12:00 13:00 14:00 15:00
Water level (in ℓ) 6 392 5 627 4 845 4 072 3 308 2 530

Tank B

Time of the day 10:00 11:00 12:00 13:00 14:00 15:00

Water level (in ℓ) 8 654 7 991 7 315 6 611 5 863 5 052

Tank C
Time of the day 10:00 11:00 12:00 13:00 14:00 15:00

Water level (in ℓ) 7 358 6 571 5 743 4 942 4 163 3 333

4. (a) How much water was there in Tank B at 13:00?

(b) How much water flowed out of Tank C between 12:00 and
14:00?
(c) Which tank lost the most water in the period 11:00 to 12:00?

(d) Which tank lost the most water in the period 14:00 to 15:00?

(e) How much water, in total, flowed out of the three tanks
between 10:00 and 15:00?
5. Complete a table like this for each of the three tanks.

Period of 10:00 – 11:00 – 12:00 – 13:00 – 14:00 –
time 11:00 12:00 13:00 14:00 15:00

Water lost (in ℓ)

6. Look at the numbers in the tables that you completed in
question 5. If Mr Naidoo continues to water his plants for the
next 24 hours, at what times do you think the different tanks
will be empty?

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