Answer :
Final answer:
To make concrete, the total concrete that Hassan can make is 21 tonnes, and he needs 7.5 tonnes of sand for the 3 tonnes of cement, based on the given ratio of cement, sand, and aggregate which is 2:5:7.
Explanation:
The question involves the application of the concept of ratio in mathematics and an understanding of concrete mixtures. The given ratio for cement, sand, and aggregate is 2:5:7.
This means for every 2 parts of cement used, 5 parts of sand and 7 parts of aggregate are required.
A) In relation to the total mixture, the part representing the cement is 2 out of (2+5+7) =14.
So, when 3 tonnes of cement is used, the total concrete prepared = 3 tonnes * (14/2) = 21 tonnes.
B) The amount of sand required is 5 parts for each 2 parts of cement.
Hence, if 3 tonnes of cement is used, the amount of sand required = 3 tonnes * (5/2) = 7.5 tonnes.
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