السؤال 65

A rectangular garden measures 15 metres by 8 metres. Inside it lies a rectangular pond measuring 5 metres by 4 metres, and grass covers all the rest of the garden. Select all the statements that are true about this garden.

The grass covers 100 square metres.الإجابة الصحيحة
The grass covers 120 square metres, the area of the whole garden.
The area of the pond has to be taken away from the area of the whole garden.الإجابة الصحيحة
The grass covers 20 square metres, the same amount as the pond.

الشرح

The garden as a whole covers 15 times 8, and the water occupies 5 times 4 of those squares, so what is left for grass is 120 minus 20. Quoting the full 120 counts the pond as though grass grew across the water, which is precisely the step that the subtraction exists to undo.

الشرح

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